78 Times People “Did The Math” And Revealed How The World Really Works (New Pics)
When I was in middle school, I had a classmate who would look at trigonometric functions and yell, "I will never need these!" A lot of us had similar thoughts but wouldn't say them out loud. But there's a subreddit that proves otherwise.
'They Did the Math' is full of useless yet fascinating calculations for all of us normies who can't crunch the numbers ourselves. From how many flies it would take to lift an average person to how fast a Godzilla-sized snail would crawl, here are some of the most interesting questions—and answers—we found scrolling through its feed.
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How Fast Would A Snail This Size Go?
innnerness: If we take it literally, assuming the snail is roughly the height of a five-story building (say, 15 meters tall), that’s about 1,500 times larger than a typical garden snail (~1 cm tall). Speed scales roughly with the square root of linear size if muscle power and proportions stay the same. So: Average snail speed: ~0.03 mph (0.048 km/h). Square root of 1,500 ≈ 39. 0.03 mph × 39 ≈ 1.2 mph (about 2 km/h So, this Godzilla-sized snail would crawl at a slow walking pace, fast enough to make “Walk for your lives!” actually sound like decent advice.
"Speed scales roughly with the square root of linear size". Correct!
I believe the math, but I'm skeptical about the underlying premise applying to snails of unusual size.
Why not? Have you seen what the Japanese did with simple bugs in the 50s? 😅
Load More Replies...Is The Math Here Accurate?
whynotthebest: Math is correct but the words are not. This is similar to stating that the 2010 federal minimum wage of $7.25/hr could buy you 72.5 Bitcoin after an hour, and since 72.5 Bitcoin is now worth $7,568,659.25, then federal minimum wage was $7,568,659.25 in 2010.
Assembly line work does not require a degree or certification and is therefore unskilled labor.
Load More Replies...Ford only paid a worker $5 a day for an "extraordinary day". The usual wage for most workers most days was much lower.
How Much Would The Cat Have To Weigh For This To Be True?
SecondaryWombat: So it looks like my laptop take about 50g of weight to press a key (Source: I put my laptop on a scale and pressed keys). Standing still a cat stands on all four legs (I am choosing to extrapolate the existence of this kitten's other back leg). So while not moving, with its paws on only one single key each (which we can see from the photo is not correct) the kitten would need to weigh 50x4=200 under 200 g. However, it looks like each paw that we can see is on a minimum of 2 keys and that changes things substantially. 2.5 keys/leg x 50 g/key x 4 leg/cat = 500 grams/cat, and look the units cancel, so that means my math is right. A 500 gram kitten is about 5 weeks old, and that also looks correct visually.
My kitten just hooked a claw under the edge of a key, yanked the thing off, put it in her mouth, spat it back out, then stared at me until I got her something to eat (so I'd have peace to fix the pieces).
Oh, just wait until it gets large enough to post. My cat had fans in several forums because I always forgot to lock my keyboard. Her comments were largely misunderstood but funny nevertheless.
BUT - at 0200 in the morning, the cat walks across your face with the weight of two elephants!
That might be accurate for a tiny kitten place gingerly on a keyboard. For a kitten walking under its own power the weight will only be on 3, or even 2, paws at some times and the weight won't be uniformly distributed on the paws. Also, keys can be depressed by force as well as weight, so even a 35 gram cat could sometimes be capable of applying 50 grams of force with a single paw.
Cool, but how did that kitten do all that math before it stepped on?
Cats have even more abilities than one might suspect :-)
Load More Replies...My six week old kitten came knowing two phrases: No! and Get Off The Keyboard! She perfectly struts down the tiny stip of plastic beneath them instead.
Would 4 Balloons Be Enough To Lift That Small Boi?
electricsoldier96:
They did it on MythBusters, with 3500 balloons and a 44lbs child. If this is a 20lbs Dachshund, it would took 3500 / (44 /20) = 1590 balloons.
I didn't need to do the math, his back is not curved & his feet are flat
A cubic metre of helium has a mass about 1 kg less than the same volume of air at room temperature and atmospheric pressure. Let us suppose a typical balloon has a volume 12.5 litres. Then it will take about 1600 such balloons to lift a weight of 20 kg. What a waste of helium!
Could They Actually Still Make A Profit?
e-war-woo-woo: Tesco is slightly over on Google figures for 2024 3128 million profit, 330,000 world wide employees = 9478 per employees. So if they paid 10k extra they’d be makings loss. But they could defo do 5k extra and still make a healthy profit.
But what about shareholders? Will someone think about the poor shareholders who'd have to buy 20 less rental houses to speculate with? That'd make them sad!
While I do understand what you're saying, pension plans, 401k plans, etc. are shareholders as well
Load More Replies...You really need to understand who owns tesco and British gas. Hint: it's millions of different people making tiny profits, not a single person making huge profits.
Not the point, don't post record profits as a company and then raise your prices again in an already struggling economy. Thankfully other options are available - all the other options just have to undercut them by a tiny bit for people to come to them.
Load More Replies...While Inspiring, Is This The Most Efficient Way To Move A Bookstore Around The Corner To A New Location?
Single_Blueberry: A human chain is probably the most efficient way if you HAVE to use this many people, because they would block each other if they moved. Could you do it just as quickly or quicker with much fewer people? Probably. More importantly though, it's fun to do it this way and a good opportunity to socialize.
ya_mamas_tiddies: This is 100% the most efficient way, as none of those folks are getting paid for this. What can be more efficient than free manual labor
If you are using human labour to move the books, then a chain is far more efficient than carrying the books. With a chain, the humans stay still, and the books go from A to B, once. If a smaller number of humans carry the books, then they have to go from A to B multiple times. At least half the travel is wasted time, because no books are moved from B to A, only A to B.
I helped pack up a massive used book store and that's how the upstairs books all came down the stairs.
This is why they used to have bucket brigades before the invention of tanker fire trucks?
Only if money is your only criterion of efficiency. Sounds a lot like capitalism to me!
They Worked It Out Before They Worked It Out
shelmich: If his weight doubles every 3 months, then by the time he hits 10, he'll have doubled 40 times. So if he's 7.5 trillion when he's 10, then we can solve for his birth weight in the following equation: 7.5 trillion lbs = x * 240 This gives x = 6.8 lbs, a very reasonable birth weight.
I used to be able to do this. Kind of cruel how our brains deteriorate with age but can still remember when it was sharp.
We should probably turn the kid to steel in the great magnetic field, just to give him an edge
Load More Replies...Ah, sum of GP. The bane of my existence, especially in this problem where you have to calculate with numbers like 2^40
What Would Happen To The Turkey If You Did This?
jeffscience: This is 10x the estimated temperature at the site of the nuclear blast at Hiroshima. The turkey would cease to exist in any recognizable form.
Darn, it looks like jeffscience ruined what seemed like a perfectly reasonable alternative.
Typically a chemical reaction proceeds about twice as fast for each 10 Kelvin rise in temperature. Let's assume cooking is a chemical reaction obeying that rule of thumb. So if it takes about 4 hours at 175°C, it should take about 1 hour at 195°, 1 minute at 255°, 1 second at 315°. But it's not going to work because it takes time for the heat to be conducted to the centre, so the outside will be burnt while the rest stays raw. Better to follow the recipe.
I would not be upset if the turkey was vapourised and not making it to the table
The math on this is completely wrong. The Fahrenheit scale doesn't start from absolute zero, so 700°F is less than 50% hotter than 400°F . The proper temperature conversion is 809.67 * (4 * 3600) - 459.67 = 11,658,788.33°F
If You Made $7000 Per Hour Since The Birth Of Jesus Christ, When Will You Surpass Jeffrey Bezos, Current Net Worth. What About If His Net Worth Expands At Its Current Rate?
GIRose: Jeff Bezos' net worth, ~$210,000,000,000 210 billion/7000 = 30,000,000 hours to surpass him. There are 8,760 hours per year So ~3,424 years to catch up to Jeff Bezos' current wealth at $7000 an hour if it was expanding at it's current rate, literally never because it expands by ~$8,000,000 an hour.
No one. Absolutely no one, needs to be that filthy rich. Emphasis on the filthy because we've all heard how his workers are treated...
Billionaires will likely be the ultimate cause of the end of American democracy.
Load More Replies...These billionaires are nothing but hoarders. Well, OK, dickwad hoarders,
If you earn $1 per hour, it would take you 114 years to amass one million dollars. At the same rate of pay, it would take you 114,155 years to amass one billion dollars. Tax the rich.
I didn't check your math, but it doesn't matter. The last sentence is absolutely right, regardless of any calculations.
Load More Replies...I knew Jeff Bezos when he first started Amazon. His business model was to s***w over his vendors, his workers, and the communities where he built his warehouses. He’s completely unscrupulous, he’s phenomenally dishonest and corrupt, and he cares for one person and one person only: himself.
Load More Replies...This Feels Untrue
UncleCeiling: There are about 13,500 McDonald's restaurants, each with an average of 50 employees (As per McDonald's 2023 numbers). A large McDonald's fry has about 80 fries in it (numbers seem to vary from 75-90 depending on where you are getting your fries, and it costs $5 (note that that's retail, not what the company actually pays) for a total of $0.0625 per fry. So if every employee (not just the ones on staff) ate a single fry every day it would cost the company $42,187.50 based on retail fry numbers. For individual stores, it wouldn't even average the price of a large fry.
they went a very complicate way to arrive to this conclusion... average store has 50 employees, so it means 50 fries per restaurant. So less that a large fry...
There is more wastage than that in the kitchen with spills and what is left at the end of the day.
There's way more than that. McDonald's throws away any food that's been sitting too long. Literally dozens of hamburgers a day.
Load More Replies...I don't know what everyone else got to see but for a dose of irony here's a screenshot of what I'm seeing. next>
I stole a lot of nuggets when I worked there and they didn't go bankrupt
Or you could just cook more of those $0.0625 fries at a cost of $5 and write it off as standard business loss against your tax return 😆
I’m Really Curious— Can Anyone Confirm If It’s Actually True?
escaping-to-space:
Aircraft carrier ~ 13
Billion American homeless ~ 800 thousand
High-density construction cost ~ $350/square foot
13B/800K = $16,250 available per person
Divided by 350/sqft = 46.4 sqft per person (of new construction)
So depending on exact construction costs or repurposing old buildings, you could get a ~5x10 room per person. Not enough to house everyone, but I suppose technically enough to shelter everyone. Since that room doesn’t have space for plumbing or kitchen, you might be able to construct for less than $350/sqft and then maybe squeeze out a bigger room or have some shared bathroom/cooking areas but that still isn’t housing.
Though, while I know we pump a ton of money into military, the price of one ship did give more per person than I initially would have guessed.
And how much would it cost to build the 20-25 "battleships" that trumpolini wants to build?
It seems Republicans are OK building detention centers for people of color deemed evil, but are not willing to build homes for homeless veterans.
Here’s a fun fact: the Department of Defense has failed its last 8 audits, to the tune of hundreds of billions of dollars. We shovel the money in, but no one has the faintest idea where it goes. And as a reward for this financial malfeasance, the next defense budget is over one TRILLION dollars. How sweet it is.
Buying the land for said tiny homes would add to the cost. Also bribing the elected officials to allow housing, that's another billion
Is This Even Remotely True?
Yes N64 cartridges vary between 4-64Mb
388x 64= 24,832Mb so 24-25Gb if they were all max size.
So they would easily fit on, especially once you account for the smaller games.
Fun fact - Someone I know has a Gameboy type device that contains 14,000 older classic games. It has 128GB of storage, and no, I haven't counted the games on it to check. It was also cheap for a console at around £50. I'm pretty sure it's not entirely legal because of copyright issues. Someone I know got it off Amazon. If you want one, you'll have to do the Googling yourself. I think it was a good purchase.
And I remember when a 20MB harddisc was massive (both in terms of storage and physical size). But, than, the computers that it was connected to had 32K onboard, so in relative terms it was pretty huge.
My first computer, I didn't get a hard drive, because what would I possibly do on it that wouldn't fit on the 2 5.25 floppy drives.
Load More Replies...If Every Person On Earth Went For A Swim In Lake Superior, How Packed In Would Everyone Be?
Appropriate-Falcon75:
The area is about 82,000 km2 , and there are about 8.2bn people on earth. Which means that each person gets about 10m2 . So, if you arranged people in a grid, there would be about 3m (or 10ft) between each person.
Let's assume the average person (adults and children, skinny Asians as well as obese you-know-who) has a volume of 61 litres below the neck -- we'll allow them to keep their heads above water. So together they'll displace about 500 million cubic metres which is half a cubic kilometre -- given the large area of the lake it wouldn't raise the level very much. What proportion can't swim? Well, it might not be so bad if they drown: it's an overpopulated world.
Most people would die from hypothermia before they drowned. That deep water never warms up to a comfortable temperature to swim in for more than a few minutes unless one has a wet suit on.
Load More Replies...Think of the environmental impact of eight billion people having a quick pee.
Also the "get me the hell away from your pee"-impact!
Load More Replies...Lake Superior is freakin huge. Source: Lived in Michigan all my life and have been on it. Its the size of small sea. Has it own weather too. The storms are like mini hurricanes.
Since somebody didn't do all of the math I did. All those people are going to displace an enormous amount of water. Almost 17.5 billion cubic feet of it. That's going to raise the water level, and therefore the surface area of the lake. As a ballpark figure, the 0.012" of extra water is going to give everyone an extra 3.7 square millimeters of space.
Once they're all in the lake, how many piranhas would it take to finish them off?
You mean "to finish us off". You will be in there as well. 🤭
Load More Replies...How Can This Be Right?!
A_Martian_Potato: This is a very well known mathematical problem. The post is correct. It's one every student in a undergrad level statistics course does. I won't go over the math to prove it, you can see that in the wikipedia page if you want, but the thing to keep in mind is that you shouldn't be comparing the number of people to the number of days in a year. You should be comparing the number of PAIRS of people to the number of days in a year. In a room with 23 people there are 253 pairs you can make. In a room with 75 people there are 2775.
Essentially you compute the probability that all 23 birthdays are different. This turns out to be a little smaller than half (49.3%) . So the alternative, that two or more birthdays are the same, has a probability of a little more than half (50.7%).
Most people misinterpret the answer as meaning there’s a greater than 50% chance that they themselves will share a birthday with someone else in that group of 23. Those odds are only 2-3%.
Amarillo Slim (famous gambler) used to go to a car wash and bet somebody that two people waiting in line had the same birthday. He almost always won.
How Many Pennies Will Be Needed To Make This
STK_Pixle:
A penny made before 1982 is 3.11 grams and consists of 95% copper, so taking 95% of 3.11 is around 2.95 grams. 1 penny = 2.95 grams of copper There are approximately 454 grams in a pound, and Lady Liberty is made of 62,000 pounds of copper. 454/2.95 = 153.9, which would round up to 154 pennies for one pound of copper. 154 × 62000 = 9548000 So in total, you would need 9,548,000 pre-1982 pennies, or $95,480 in face value, to make a second statue from just pennies.
You would also need the iron frame. It is an iron frame with copper around it. So it would cost a lot more than $95k.
Iron is one of the most abundant elements on the planet, so "a lot more" is relative
Load More Replies...What gives you the impression she's gay? She was modeled after Eiffles' mother
I don't think you understand how girlfriends works. Only (some) men think it has anything to do with s*x.
Load More Replies...How Long Would This Take?
PolyPorcupine:
Spotify says it has 100 million songs and 6 million podcasts, average length of a song is 3 minutes, the average length of a podcast episode is 41 minutes, and the average amount of episodes of a podcast are 10. Also they have 350k audiobooks, at an average length of 10 hours. So you have 300,000,000 minutes of song And 2,460,000,000 minutes of podcasts and another 210,000,000 minutes of audiobooks. Totaling around 3 billion minutes of content. Calculating it's around 5707 years, if you listen to it at 5707x speed you'll be done in a year, easy. Though google also says that around 100K songs are added every day, so once you are done with those you'll have another ~300k minutes every day.
"So you have 300,000,000 minutes of song" meh, amateurs, symphonic metal songs are longer. 🤘😂
I'd like it better if Spotify was cheaper, if not free, like Libby, the library app with audiobooks, magazines, graphic e-novels, and e-books. And you can sign up for multiple accounts with separate libraries.
[request] Did They Actually Do The Math?
Ritterbruder2:
A sphere has the lowest surface area to volume ratio of any shape. It’s going to have the lowest glaze to dough ratio of any pastry.
Could This Be Accurate?
Warm-Finance8400: That would translate to the average person being drunk 0.7% of the time. A week has 168 hours, 0.7% of that would be ≈ 1.2 hours per week drunk. Seems reasonable to me.
The average person spends nowhere near 1.2 hours per week drunk. I don't think there are enough alcoholics to make up the difference.
Well, we do need to establish what is meant by drunk, but, back in my youth, when I still drank, I would get off shift at the restaurant at 11:30 and typically hammer a couple of beers right away, so by midnight I would have a bit of a buzz. Normally would continue to drink until 2 AM or later. Definitely alcohol affected the whole time. That's 10 hours a week. Add 4-6 hours every Saturday and it starts to amount to a lot. Then there were the guys at work who actually drank quite a bit. Not unusual for some of them to come in at 3:00 (15:00) with a good buzz on and maintain that until 2 or 3 AM. Honesty, among blue collar types I'm going to say 1.2 hours a day, let alone a week, is conservative.
Load More Replies...Is This True?
Public-Eagle6992: I‘m not sure how exactly the statement is meant so I’ll interpret it one way but also state other ways how it could be interpreted. "The ten richest men…" could either mean each of them individually or all of them combined. I‘ll go with individually. "Their riches wealth" I assume this means net worth "Richer than 99%" could mean the wealth of the 99% combined, could mean the average wealth of the 99% or could mean the highest amount of money anyone in the 99% has. I‘ll go with highest Wealth of 10th richest person: 121 billion. -99.999% that’s 1.21 million. 1.1% of adults have at least 1 million, so when having 1 million, you can still be in the lowest 99%. So it might be true, it’s close.
(gregorian chanting) Tax the rich! Tax the rich! The rich: Did they just say "more tariffs?"
Load More Replies...If you’re looking at the world’s population, someone with $1 million could lose that percentage, and be wealthier than 99% of the population.
Is This True? Only 33 Wins?
wayoverpaid: This assumes a single elimination, best of one tournament. Say something like rock paper scissors or a coin flip. You need one round for the finals. So one game for the finals. Semifinals has four people, quarter finals has eight people. Each round cuts the field in half. The winner only needs to win one round from that game. With 33 rounds, you get 233 people. That's 8,589,934,592. World population is under 8.3 billion. So the winner MIGHT get a bye in the first round, and only have 32 games. But 33 games guarantees the win.
It's basically 2 to the power of 33 (or whatever takes it beyond the world population). Ignore the 233 people, that's irrelevant and confusing. Also worth noting that with a strict knockout with N participants, one needs N-1 games to take place - it doesn't matter about byes. That's derived from the fact that everyone loses once, apart from the winner.
It's actually 0.5^33. 8,265,136,454 * .5^n =x. For n=33 x=0.96. It may be even easier if you just repeatedly divide by two because you can do it in 15 seconds with a calculator. FWIW, When I asked Google about world population it gave me an even number but the first round leaves an odd number of people, so that thoroughly screws up the idea of having everyone pair up in twos. We can't hold the contest until population goes up by 324,798,138 people.
Load More Replies...One nice lucky streak, and I'll be #1 in the whole world. I am counting on this to be true.
Your waste paper bin must be knee-deep in lottery tickets then
Load More Replies...Assuming She Falls And Directly Into The Water, What Are The Odds She Survives? At What Height Is A Death Of Human Falling Into Water Inevitable?
natesplace19010:
It’s basically 99.99% fatal at 200 ft or more. That said, there’s always a chance but it would involve an act of god like a hugely perfect gust of wind or the water randomly getting airated by underwater gasses.
Old people will tell you that a fall from just one metre can be fatal if you land badly.
People who don't realise this, are not noted for their longevity
Load More Replies...It all depends on the landing. If she landed feet first or hands first in a perfectly perpendicular position, hitting the water with the smallest possible cross section, then it is survivable. Anything other than that will almost certainly be fatal, either instantly from the impact or from drowning due to being unable to swim due to her injuries.
Walter fell from a plane without a parachute and a perfectly timed underwater b**b provided enough aeration and he survived!
How Many Layers Of Paint Would I Need To Fill In A 5m X 5m Room
CHG__:
Assuming a paint layer is 100μm thick it would take 10,000 layers to equal 1 meter of thickness, so 5 meters would be 50,000 layers.
That's painting just one wall, filling the space toward the opposite wall. Normally one paints all four walls, so half as many layers are required, but the area (and thus the volume) of each gets smaller each time. How long is it going to take to apply 25 thousand layers of paint?
You could probably get it done in one lifetime, if you just do one layer per day and let it dry, that's ~68.5 years
Load More Replies...I’ve always thought about this question a lot, thank you for this answer. I should’ve calculated this on my own tbh, was a very simple problem
I've always said, if you removed every layer of paint from our 100 year old Middle School, it'd pop 3 feet out of the ground.
How Long Would One Person With A Shovel Need, If They Work 8 Hours Per Day, 7 Days A Week?
anon:
This river looks to be 100 miles wide, and stretches about 2700 miles. lets give it an average depth of 15 feet. converting everything to feet 15 x 528000 x 142560000 = 1,129,075,200,000,000 cubic feet Assuming you had a human who could work 8 hours straight without tiring and can shovel 1 cubic foot every 15 seconds (with a crew to help move the dirt he shovels). This would take 282,268,800,000,000 minutes or 4,704,480,000,000 hours or 196,020,000,000 days or 537,041,096 years.
That calculation isn't adding the extra material you need to dig to get through the mountains and hills on the way. If you want to be 15ft below sea level for the ditch, you need to remove much more than 15ft in most places along the route
But if 150 M humans worked in this, it would take 3y 7m to comeplete if math above checks out. But also the pesky land elevation you talk about 🙃
Load More Replies...Using normal width canals between navigable rivers would make this much easier.
This is something like the Rhinoceros party we once had. Their promise if elected was to bulldoze the Rockies into a gradual slope to the Maritimes so you could coast coast to coast across Canada.
Or just go via the Panama canal...the curiosity of which is that it runs north-south, not east-west.
And the "eastern" end is west of the "western" end.
Load More Replies...Could This Be Done?
For each beer a single American drinks, a brit would have to drink nearly 5 based on numbers alone.
American beer is mostly like sėx in a canoe, though. Fûcking close to water....
Except most craft beers in the US average 8-10% abv compared to the 6% average in the UK, nice try though. If you're talking about Bud, then sure, but no self respecting drinker would even touch that
Load More Replies...Now, if either country concentrated on *thinking* instead of *drinking* , we might achieve something.
Your average Wisconsin college kid drinks more than your average British pub.
The UK drinks only slightly more alcohol per person of drinking age than the USA. Like 20% more, but that's legal liquor. The USA has a much higher proportion of out and out drunks and deaths from alcohol, illegal liquor in the USA is the problem.
Eliminating the sober and other non-drinkers (due to age and medication taken and other factors)
Would 20,000 Flies Be Enough To Lift Me?
Surly_Dwarf:
No. Almost 5 million flies (or 437k bumble bees, or 65k monarch butterflies, or 10k hummingbirds, or 2.9k sparrows, or 1.9k fruit bats, or 441 pigeons, or 25 bald eagles) to lift a 110 pound person.
Did They Avoid Retinal Damage?
ModeMysterious3207:
Assume typical sunglasses with a 30% transmission. Is that seven pairs of sunglasses? 0.37 is 0.02% transmission. Recommended for solar filters is 0.001%, so, not dark enough. Eye damage? Depends on how long you look
And no, looking through an old floppy disk isn't safe either. It does work as an IR filter (Infrared) but not enough. A welders helmet or the lens of one works though.
Welder's glass works but you need to check it's strength because they have stronger and weaker versions
Load More Replies...It's 0.3 (30% transmission) to the power of 7 = 0.0002 = 0.02%. The original post displays it as 0.3 with the 7 in smaller letters above it, and that layout can get lost when copying information, making it look like 0.37 instead of 0.3^7
Load More Replies...Depends on how long you look. I've looked briefly (5 seconds) at a total eclipse without sunglasses and not had any damage from it.
I have actually done that. It takes at least 3 sets of sunglasses to be able to see the sun ok. But a welding mask is best.
Is This True?
Angzt:
Let's go with the following assumptions: Rat lifespans are around 2-4 years, so we can (kind of) ignore them dying off. Rat pregnancies last around 25 days, with a few days recovery before the next pregnancy, let's round that up to 30 days. Rats reach adulthood at around 60 days. The size of a rat litter is around 6 to 18, so let's go with an average of 12. Let's also only look at the female rat population and then double at the end. It'll make things a bit easier. So our litter size is only 6. Since our pregnancy and time to adulthood are both divisible by 30, let's go with 30 days as our time period. Then 3 years are 365 * 3 / 30 = 36.5, so 36 time periods. Now, we need to track 2 variables: The number of adult femal rats (a) and the number of newborn female baby rats (b) in relation to our time periods. We know that we start with 1 adult female rat and 0 babies. So: a(0) = 1 b(0) = 0 We also know that the number of adults at any given time is the number of adults of the previous time period plus all the newly matured rats. The latter being the baby rats from 2 periods ago. So: a(t) = a(t-1) + b(t-2) Finally, the number of newborn rats is simply 6 times the number of adult females in the preceding period: b(t) = 6 * a(t-1). As you can see, we actually vastly exceed 482 million rats by the 36th time period. In fact, we get up to 2.7 trillion adult rats.
Not if the cockroaches have anything to say about it! But, then again, cockroaches rarely talk.
Load More Replies...They'll probably not make it to 5,000 if they were anything like the mice in the Universe 25 experiment.
How Fast Should Loki Have Been Falling After 30 Minutes?
Squeaky_Ben:
Terminal velocity for a falling human is around 200 kilometers per hour. You reach this velocity within the first 30 seconds of the 30 minutes, so the acceleration portion would be negligible. So, around 100 kilometers of falling, give or take a little.
Fun fact: some smaller animals like squirrels can almost never reach their terminal velocity through falling
Fun fact: Some smaller animals, such as squirrels, will reach terminal velocity in less than 20 feet or so. If a squirrel falls there's a fairly good chance they'll land at terminal velocity.
Load More Replies...How Many Packs Of Mentos And Bottle Of 2-Liter Coke Would Be Needed To Launch Into Space?
james_pic:
I've seen YouTube videos where they manage to get Mentos and Coke jets about 10m into the air, which would give the jet an exhaust velocity of 14m/s. Wikipedia tells me low earth orbit needs a Δv of about 9.5km/s. Plugging these numbers into the Tsiolkovsky rocket equation gives a wet mass of 2.5 * 10^297 kg.
The observable universe has a total mass of 1.5 x 10^53 kg.
Rocketry calculations are fascinating. With diet coke and Mentos it can't be done. With black powder hobby rockets it would take a literal mountain of them to get into space. With a high power multistage hobby rocket you can put a payload of 1 gram into space for a cost of only about $1,000, but to do that needs excruciatingly accurate machining tolerances.
Just tell them there are no taxes on Mars, they';ll put themselves in it
Load More Replies...I think I could calculate this too, I’m too sleepy to check my notes and do the working though. I’ll do it tomorrow morning
How Long Could A Candle Of This Size Last?
Kionimom1: It really depends on what wax the Candle is made of and how the wick is Placed inside Lets say its paraffin wax and the size of the candle is 1 cubicmeter meaning 1000000 ccm. The density is 0,9 g/ccm. So the candle would be around 900 kg (i have the feeling there is a mistake here). A normal paraffin candle burns about 7,5 grams per hour so it should burn for about 120000 hours or 13.6 years, considering it doesnt heat up too much Also, if the candle is Constantly heating up for hours it burns down a lot faster than lighting it on and extinguish it every half hour. Thats also why you shouldnt keep normal size candles lot for more than 5 hours because the heat can potentially get so Hot nearby stuff Catches fire.
I make candles as a hobby. I made one in a jar with 4 wicks and it got so hot all the surrounding wax caught on fire, not just the wicks. Good thing I was watching it, never leave a candle unattended. There was a 15" tower of flame on it. I used very soft soy wax though.
Soy wax is problematic. I've had soy candles split, spill wax everywhere and catch fire. I'll only burn the ones that are in a jar now.
Load More Replies...If it's a normal candle wick it will melt just a small pool of wax, so we'll end up with a small hole running down though the block -- and the flame may go out before the hole reaches the bottom. The picture shows a much larger wick, proportional to the size of the candle, so it will burn much more than 7.5 g per hour and give off plenty of heat: I wouldn't light it indooors!
How Did They Get To $700mil
Butterpye:
Some company estimated employees will take a 20 minute break during their work hours, they figured there would be 84 million workers on that day, and they multiplied the amount of time with the hourly wage for people over 16 and which is like $24 or so dollars and got $694 million.
Calculating reduced productivity compared to other days is pure math and passes no judgement.
Which is why we have laws to tell these idjits they're doing the wrong kind of thinking.
What If All American Parking Lots Are Covered By Solar Panel? How Much It Will Cost And How Much Energy Will Be Generated?
Martensite_Fanclub: I used to work in solar and this question isn't easy to answer - there are just too many variables. Cost and generation are affected by: location, time of year, panel crystallinity, spacing, and many other factors... But if you need a rough estimate, we were able to get about 1.1 MW (or about 1.72 GWh/yr) (or about $2.20 per Watt after tax credits, etc) on a 315-space parking garage roof in the southern Florida region. These were 3,000 monocrystalline panels (more efficient but more expensive) and ofc these were closer to the equator and get more sun so not everywhere would generate as much. Use these numbers per parking space as a rough estimate if you're in a similar latitude and adjust energy generated down by 5-30% if you're staying in the US (although using Solar Map is more accurate. For example, you may get about 12.79 MW/4.37GWh/yr for 800 parking spaces (or the average Walmart parking lot) in south Florida, which is enough to support ~415 homes year-round, which is probably what you really wanted to know.
It's not just the energy production, it's keeping the cars in the shade and thus cooler
And protecting the cars from hail by making the hailstones hit the solar panels.
Load More Replies...Wine farmers are beginning to counter the risen temperatures by combining their vineyards with solar power. Keeps the crop cooler and generates power. Thus the initial question is'nt even always valid.
Also being used in pastures for animals like sheep. Gives them shade, saves on water & overheating.
Load More Replies...Tens of millions of acres of farmland grow corn distilled into ethanol to burn in car engines. Is that somehow better?
If you had EV charging at the car park, this would probably make sense. For about 10 cars in this case, when it's sunny.
How Heavy And How Much Will This Be?
Nahanoj_Zavizad: Assuming it's approximately 1.5m in each direction, and solid. Tungsten density is 19300 KG per M3 So it would end up weighing about 60-70 Tonnes. carajillu: mtu in metals trading is equivalent to 10kg, not 1000, because it refers to 1000 kg of the brute ore which is around 10kg of pure metal. So, 70 tones is 7000 mtu, which cost in current prices around 330$, which results in 7000*330= 2.310.000$
Would This Extend The Range By Any Decent Amount?
somehugefrigginguy: I'm not a car guy, but best I can tell that is a 2019 Lamborghini Huracan which gets about 15 miles per gallon. The tank on top looks like a 275 gallon IBC tank, so ignoring aerodynamic effects it would add about 4,125 miles of range. That tank mounted in that orientation adds approximately 13 ft² of frontal cross section plus parasite drag so at highway speeds this could reduce fuel economy by as much as 50%. So if we assume a fuel economy of 7.5 mpg, that tank would add 2,062 miles of range.
Yes, but in a beat up old 4WD ute, not a Huracan.
Load More Replies...There's little reason to carry more fuel than the time it takes to fill your bladder. Most gas tanks (in the US at least) are good for a max of six hours of highway speed.
Really? That sounds unlikely. What capacity is the tank? If it's a standard tank size you'd need to be scoring about 70mpg, which is basically not happening, even on a rolling road, let alone with wind resistance etc.
Load More Replies...Assuming those are US gallons, the tank holds 1040 litres. The consumption of 15.7 litres per 100 km increases to twice as much (!) and the range is increased by 3318 km. I feel it would be better to buy a more economical car instead; these days some use less than 6 litres per 100 km.
Did It Actually Produce That Much Energy?
Solondthewookiee: No. The design power of Reactor 4 was 3,200 MW. Over 40 years, it would release 4.0e18J, which is 20 times the energy released by Tsar Bomba. Since Chernobyl did not culminate in the largest nuclear explosion in history by an order of magnitude, we can say that the meme is inaccurate. The last reading from the instruments during the accident gave a power reading of over 30,000 MW. The reactor exploded almost immediately after, but it puts us in the ballpark of 10x energy production.
Is This Actually True? How Does Someone Even Verify It?
Ok_Programmer_4449: The internet currently stores about 1.4x1024 bits, and it takes about 100,000 electrons to store a bit in an SDRAM, so if all the data on the internet were stored in SDRAM you're talking about 1.4x1029 electrons, or 140 thousand trillion trillion electrons which would weigh about 130 grams. So you're in the right ballpark. It's a few strawberries. But most data on the internet is not stored in SDRAM. Most data is still stored in the alignment of iron atoms on mechanical hard disks. It takes about 20,000 iron atoms to store a bit. So you are talking 2.8x1028 iron atoms, which weighs about 2.6 metric tons, which is about the weight of 52000 strawberries.
So you're telling me that with enough time and dedication, I could eat an internets worth of strawberries.
I assume 1024, 1029, and 1028 are meant to be 10^24, 10^29, and 10^28
So it'd be THEORETICALLY possible to compress the entire internet into an apple-sized object and, like, send it to the past or launch it to space? (I'm watching Steins;Gate so bear with me)
Are These Numbers Realistic Or Is It Just Nonsense?
InfallibleSeaweed: It's a real, albeit optimistic calculation. What this doesn't mention is that nobody knows what $2.8 million will be actually worth in 50 years. It will in pretty much any scenario be worth more then if you had not invested it, but don't expect to be a millionaire by today's standards.
Help Me Settle A Family Debate! How Unfair Was The Slice Of Pie? Was It More Than 25% Of The Pie?
antilopelore:
I converted the picture you posted into a bitmap to make it simpler. I replaced the remaining cake with white and the part you cut off with black. Then, I simply counted the number of pixels of both colors, giving me the following results: White Pixels: 127,200 Black Pixels: 47,753 Which totals: 174,953 pixels in total. After that, I simply calculated the ratio of the number of black pixels to the total number of pixels. 47,753 / 174,953 Which gives us: 0.2729 This means that what you cut off was 27.29% of the total cake.
How fair or unfair the slicing was depends entirely on how many people wanted some. And how much they each wanted, of course.
Why Is It Not 1?
Electronic_Finance34:
There are 100 people, and 99 are lefties. That means there is 1 right handed person. What would cause the 1 right handed person to double in representation from 1 to 2%? If the one right handed person was in a room with 49 lefties, they would then be 2% of the total. So 50 lefties need to exit the room.
For the doubtful or the algebraically inclined: Solve (99-x)/(100-x) = 0.98
How Heavy Will This Be If It's Made Out Of Styrofoam?
gurneyguy101:
32kg/m3, 5.5m x 0.5m x 1.5m = 3.3m3 —> x 32 = 105kg Hmm, I think it’s fair to say something’s gone wrong here. I reckon the sword is hollow Edit: or the sword is photoshop, in which case it would weigh 0kg
Styrofoam comes in different densities and can be as little as 10kg/M3, so that sword could be just 33kg.
Maybe, but you haven't accounted for the torque from the 4 meter lever arm. As a fairly rough figure the roughly 45° angle would put a load of perhaps 80kg on his hand.
Load More Replies...It must weigh 0. It doesn't even have enough density to cast a shadow.
If it was hollow, you enter into the maths of "how does this support itself". So probably Photoshop.
If it was hollow it would still be 3 dimensional and therefore a truss. To be real I'd lean toward Papier-mâché with a frame of chicken wire. Unless it's also fairly thick front to back (as we see it) you'd still need to be careful about orientation when holding it.
Load More Replies...How Accurate Is This?
RoadsterTracker:
That plot is somewhere around 15 meters of seawater rise. Sea level rise is ~7 meters if all of Greenland melts, and Antarctica is around 60 meters. It's pretty unlikely that in a mere 50 years it will be that flooded. Greenland melting will happen eventually given a 3-5 degree C rise in temperature, which seems increasingly likely, but it would take a while. The worst case models right now predict maybe a 4 degree rise in temperature by 2075, and it would still take the ice some time to melt after that.
One day, this will be in those "Posts that didn't age well" lists
On the bright side, Mar-a-Lardo would be nothing more than a tacky guilded Atlantis
The sea level rise in the 50 years between 2025 and 2075 can't be more than twice the sea level rise between 1975 and 2025. Which averaged 0.1 metres.
4.7% For All Of Us Public College?
ElevationAV: Assuming we're doing a 1 time tax on Bezos' net worth of ~250 Billion, that gives us 11.75 Billion once. Free college in the US is estimated to cost between $28B and $75B per year; Sanders plan estimates at least $48B per year; so no, a 4.7% tax on just Bezos wouldn't even provide half the funding for a single year.
Throw in Zuckerberg, Musk, & Gates, though, and we'd be getting close.
Sounds like according to these figures if we taxed all billionaires this tax rate here in the US there would be more than enough money to fund everyone's college for a few years.
How Much Money Could You Make Doing This?
u/dr_pickles69: According to some sources, the average cost of a kidney transplant in the United States was around $442,500 in 2020. However, this does not reflect the actual price that a donor would receive, as most of the cost goes to the hospital, the surgeon, the recipient, and other expenses. On the black market, a kidney donor might get anywhere from $1,000 to $200,000, depending on the country and the demand. If we take the average of these figures, we can estimate that a kidney donor on the black market would make about $50,000 per kidney. Therefore, if Deadpool sold 500 of his kidneys, he would make about $25 million.
Wouldn't that be 500 cancerous kidneys? His body is in a constant battle against the disease. As soon as a kidney is removed it would lose it's protection?
Or, if the kidney constantly regenerated itself to last forever, it would be worth more than $50,000.
Load More Replies...Selling organs is banned in the UK. Section 32 of the Human Tissue Act 2004. He would probably be fined £5000 for the first few and then sent to prison for subsequent ones.
So he doesn't sell them in the UK. Not like their laws are relevant outside of their borders.
Load More Replies...What Would Happen? Could We Survive This?
John12345678991: Well that’s over 10x increase so everything would immediately weigh like 12 times more. Every building would collapse cuz they use factor of safeties of like 2-4. Everyone standing would break most of their bones. If ur just laying on the ground outside u might be ok.
One second. Hmm. The shorter the timescale, the more acceleration it is possible to take without breaking. Humans Can generally only survive a sustained 5 g. But for very brief timescales, humans have survived 80 g. The highest recorded acceleration survived by a human was over 200 g. It's much the same for structures. The question asked for 12 g which is unsurvivable for a second, possibly survivable by humans and buildings for 0.1 seconds, and almost certainly survivable by humans and buildings for 0.01 seconds.
Best Way To Do It ?
A: 24*365
B: 60*60*24
C: 365*10
D: 60*24*7
We see that A > C and B > D. Both A and B contain 24. Lets remove it.
A': 365 B': 60*60
B is bigger by one order of magnitude.
if anyone's confused by the explanation: A is 1560, B is 86,400, C is 3650 and D is 10,080.
What Would Be It's Price If It Had Been A Real Natural Diamond?
Rhuobhe26:
It would be priceless beyond belief a literal one of a kind in the world eclipsing all other stones. The original Cullinan stone, the largest and possibly most famous of all diamonds was an uncut stone 4 inches long and about 3,100 carats. It is beyond value and was cut into 9 large and 96 smaller stones the largest of which is 530 carats. If the diamond was actually the full 4 inches in size or 100mm, with a deep cut then it would be 4,800 carats. The most expensive diamond ever sold at Auction was the CTF Pink Star, it sold in 2017 by Sotheby's for $71.2 million and was 59.60 carats. Now you can't compare the two, but just using those numbers that's $1.19 million per carat. So between 2,624 to 4,800 carats at the same price...$3.13 billion to $5.73 billion.
Is This Accurate?
tutorcontrol: Approximately, yes. Average distance is 12.5 light minutes for a ping of 1.5 million ignoring the electronics. 182 light seconds is the closest recorded position for a ping of 364,000, also as a "mirror bounce". This is why the rover has some longer commands and autonomous capabilities to break the control loop latency problem. So far, nothing with a 100 ms control loop has tried to chase it, and rocks tend to have effective pings around 3 e 12, so 1e7 is pretty good.
Of course, the rover is not dodging other gamers shooting at it, and does not require near instantaneous reaction time...
Aside The Absurdity Of Having 3 Millions Easily At Your Disposal, Is It Possible To Live Like This?
Deep-Thought4242: The structure is accurate, the details are wrong. Treasury bonds don't literally pay you monthly. I think those pay twice a year. And the current yields are 4-5% not 8%. But that means you can buy $3 M in T-Bonds and then twice a year, you'll get about 67,000 to spend. ETA: most people with $3M+ portfolios would consider this an unwise use of it, though it is very low risk.
If the actual figure was 8% you would be MUCH better off spending $10,000 a month and reinvesting the other 10k. That way your income would grow in line with, or probably exceeding, inflation. A good rule of thumb is to take HALF of the growth as income and leave the rest to counter inflation. That way your income in real terms remains about the same.
How Much More Would This Cost An Airline?
dwaynebathtub: "Normal (dumb) route": 5,650 miles "AI-powered route": 6,340 miles I used distancefromto.net and the Google Maps "Measure distance" tool. Normal route distance is 11% shorter.
SenorTron: This isn't a calculation, but for anyone wondering what's happening here the curved line is actually straight (following the curve of the Earth) and the straight line would actually be curved in reality.
This guy thinks airline route planners (and indeed sea route planners) are so stupid that in centuries of travel, no-one else has thought of this. It could not possibly be because he's overlooking some very obvious things.
He could be a flerfer. They have issues with the great circle routes.
Given That Pi Is Infinitely Long And Doesn't Loop Anywhere, Is There Any Chance Of This Sequence Appearing Somewhere Down The Digits?
tdammers:
Yes - if Pi does indeed work the way we think it does, then literally every finite sequence of digits is going to be present in the decimal expansion of Pi somewhere. In fact, there will even be infinitely many occurrences of it. This hinges on Pi being a Normal Number; this has neither been proven nor disproven so far, but most people seem to expect Pi to be normal.
There's an infinite number of monkeys at the door wanting to talk about this script for Hamlet they've worked out....
Well, at least one of them must've figured it out
Load More Replies...Why Wouldn’t This Work?
nog642: It would work, it would just make the water come out of your faucet a bit slower and wouldn't generate much power. Typical flow rate for a kitchen faucet is 2.2 gallons per minute say. That's 139 grams of water per second. And let's overestimate the velocity and say it's 3 m/s (6.7 mph). Then the kinetic energy of 139 g of water at that speed is 0.63 J, so the max power generated would be 0.63 W (and it would be less because we're overestimating and a turbine can't capture all the energy). A 5 V USB charger drawing 1 A, which is what those really slow basic phone chargers with none of the faster charging capabilities draw, is already using 5 W. So you couldn't even charge a phone on this if you had the water running constantly. Maybe you could charge your phone while you run your bath. But what's the point of that?
Apartment with free water, only charging for electricity and gas each month. Seriously, I think there may once have been a generator like that for running emergency radios during a power failure. Ecologically, this is a horrible idea. Solar power is much more practical.
At one time chicago had free city water, i once had a faucet mounted fan that ran off the running water, similar idea
Load More Replies...Hey, it could save a little money for those of us that want to run both the bath and a toaster at the same time.
Is This True
FriendlySceptic: 9mm Bullet: Mass: ~8 grams (124 grains) Speed: ~350 m/s (varies by load) Kinetic energy: around 490–600 joules Sling projectile (lead or stone): Mass: ~50–100 grams Speed: ~30–60 m/s in skilled hands (some reconstructions reach ~70–100 m/s) Kinetic energy: around 200–500 joules, sometimes higher. Force of the hit is comparable but the damage caused isn’t the same. A bullet’s velocity is much higher, so it causes more penetration and shock trauma, while a slingstone delivers more blunt-force trauma and can still break bones. Sort of like getting poked with a spear vs hit with a mace. Same force in the strike but very different results even though both are potentially lethal.
Similar to sling in terms of speed and mass. But much pointer.
Load More Replies...Yes. Force comes from momentum (mass times velocity) not energy (1/2 times mass times velocity squared). Injuries will be very different.
[request] Is That True?
PacNWDad: Assuming the diameter of the Dum-Dum is 2 cm, that is about 80 grams of U-235. 80g of uranium will release about 6 x 1012 joules of energy in a fission reaction. The average American uses about 3 x 1011 joules of energy per year for all use (not just home electricity, but transportation, workplace, share of industrial production, etc.). That would mean the uranium can provide about 20 years of an average American’s energy consumption. So, yeah this is in the ballpark, although about 1/4th what would actually be needed for a full 84 years. It would be more like 300g. Note that this is a little misleading, since U-235 is only about 0.7% of naturally occurring uranium. So actually, they would need to process about 42 kg of uranium to get the 300g of U-235.
The only waate is assuming it's just the spent fuel. In reality tonnes of low-grade nuclear waste is produced each year from a nuclear power plant. And that volume of waste is more problematic than spent fuel.
Yeah, uranium itself isn't particularly useful. It needs to be processed first. That's the expensive bit.
How Big Or Small Would The Room Need To Be For 1 Person To Suffocate Due To This Chain In 24 Hours?
CanoePickLocks: It’s been actually studied. For their simulation of a chain locker with roughly 21:1 air to chain ratio it was 24 hours for [fatal] levels at 23°C and 60 hours at 10°C. For exact information you would need a ton of measurements.
It's not required to have an air tank. It is required to ventilate the chain locker, test the atmosphere before entry, and have emergency breathing apparatus on standby in case there are pockets of low oxygen that testing missed. Source. I worked on ships.
This effect has caused way too many deaths of untrained staff working in corroded metal tanks. Do not add yourself to the casualty list !
Load More Replies...It's not possible to accurately calculate the rate of steel rusting from first principles. I've tried. It can only be determined from measurements.
How Accurate Is This?
Solondthewookiee: It would depend on the exact year and how they calculate purchasing power. Here's the method I used: Median home price 1970: $17,000 Median home price 2024: $420,000 Minimum wage 1970: $1.45/hr Min wage as a percentage of home price 1970 = 1.45/17000 = 8.53e-5 Multiplying that by 2024 home price: (8.53e-5)(420000) = 35.82. So not $66/hr, but several times the current minimum wage.
This only addresses the amount needed to purchase a home. It doesn't address how much you need to make to afford the property taxes, utilities, insurance, and maintenance, such as replacing the roof every 20-30 years, the appliances every ~10-15 years, etc.
420k for a home in Seattle in 224 would be very, very hard to find. Maybe a condo, but that would include the monthly building maintenance fees on top of property taxes and mortgage.
There was a boom after W22. It's gone back to what it was like before that (although a smaller boom existed after WW1 in the roaring 20s)..unfortunately booms don't continue forever, but the advances in technology and overal wealth have been dramatic.
Is There A Correct Answer?
andrew_calcs: No. It’s a paradox. B is not a fraction of 4 so can never be correct in a 4 element set with discrete correct answers. For C to be correct you would need 2 elements of the set to be 50%, so C cannot be correct. For either A or D to be correct you would need 1 element of the set to be 25%. Since there are two, neither can be correct.
This Is A Wrong Problem, Right?
49 dogs total = number of big dogs + number of small dogs(number of big dogs plus 36) 49 = x + (x+36) which can be rewritten as 49 = 2x + 36 13 = 2x X = 6.5 Can't have half a dog so yeah I'd assume something's off here.
You have to satisfy two conditions of this equation. 1) the number of total dogs has to be 49. 2) the number of small dogs has to be 36 more than the total of large dogs. And one condition is dependent on the other. Just by setting up the equation for large dogs (36 + x = 49) tells you the number of small dogs is 36 and the number of large dogs is 13. Let's look at this. The number of large dogs can't be 14 because then if the number of small dogs was 36 more than 14, the total number of dogs would be 50 and we were just told the total number of dogs was 49. Likewise, the number of large dogs can't be 12, because then if the number of small dogs was 36 more than the number of large dogs, the total number of dogs would be 48, again contradicting the number of dogs at the show. So the equation for finding the number of large dogs is the total number of dogs minus the number of small dogs, which is 49 - 36 = x, with x being the unknown number of large dogs.
But again, you're not being asked to find the number of large dogs. You're being asked to find the number of small dogs so even if you set that equation up as 49 - x = 36, with x again representing the number of large dogs, you'd still be using 36 as the number of small dogs. It's a trick question, but not in the way you think. Using the word "more" is throwing people off. Instead of saying in the problem "There are 36 small dogs and we don't know how many large dogs in the show for a total of 49 dogs", they're saying "There are 36 more small dogs than large dogs in the show for a total of 49 dogs". It's the same thing, but it's confusing people because they are asking for the number of small dogs rather than a number for large dogs which is the real unknown here, and the answer for the number of small dogs has already been given.
It's not the same thing. 36 is not the number of small dogs. We know small+large=49 and small-large=36. Rewrite the first: small=49-large. Substitute in the second: 49-large-large=36. Or 49-2large=36. So 2large=13 and large=6.5 dogs. So small=49-6.5=42.5 small dogs. You'll see there are 36 more small dogs than large dogs, and the total is 49. We don't talk about the half dogs.
Load More Replies...Can't have half a dog, but there's absolutely NO REASON why there cant be 37 more small dogs than large dogs. Or 38, etc. Words used don't specify a absolute number, merely 'at least 36'.
No, it SPECIFICALLY states that there are 36 more small dogs than large dogs. No maximum or minimum about the number. And if you work it out, there is only one number that satisfies both conditions of the question: the TOTAL number of dogs has to be 49 and the greater number of small dogs has to be 36 more than the lesser number of large dogs. That makes 13 for the number of large dogs the only possible answer if there are to be 36 more small dogs then large dogs for a total of 49 dogs. People are WAY overcomplicating the problem and the process for solving it.
Load More Replies...[request] How Long Would It Take A Teeny Tiny Black Hole, Created On The Surface Of Our Planet, To Destroy Earth?
wayoverpaid:
Cake Sprinkle isn't an official measurement, but I'm gonna pick 1mm for the size since that's my eyeball size of the dot in the picture. That 1mm in this case actually the event horizon. Such a black hole won't decay quickly. The luminosity from it will be under one watt, and the lifetime is on the order of 1047 years. The mass of such a black hole would be roughly 10% the mass of the earth, or about 10x the mass of the moon. That much mass in such a small area would immediately fall towards the core of the earth. So you have to define "destroy the earth" because having the tidal forces of an object 10x the mass of the moon falling through the core would probably create massive damage well before the earth fell into it. As for how long it takes the earth to actually be absorbed, that depends on at what point the destroyed rubble of the earth orbiting the black hole no longer counts as the earth. A hypothetical tunnel through the earth would take under an hour to fall through and out the other side. So likely by the time an hour has passed the planet is no longer stable. How long it takes every last bit of earth matter to fall into the black hole is a physical simulation I lack the power to do, but by the time you're talking about accretion disks, the Earth is pretty destroyed.
I read a science fiction book in high school about scientists creating a teeny black hole, which then got loose and started orbiting around and threatened to destroy the earth. I don't remember how it ended, but it scared me like no horror book that I had ever read. Thanks for bringing back good memories, BP! ;-)
Sounds like part of the novel Earth by David Brin.
Load More Replies...Approximately How Large Was The Font Size Before And After?
Gnochi:
With the same sequence of characters and font, you can assume that the number of pages scales with the inverse square of the font size, since characters per row and rows per page both scale inversely with font size, with a scaling factor K depending on frequency of character use and the font character lengths and kerning. Set F as the original font size, and F-2 as the new font size. K / F2 is the number of characters per page in the original, so with 30 pages we have 30 x K / F2 characters. By that same logic, 22 x K / (F-2)2 is the same number of characters. Thus: 30 x K / F2 = 22 x K / (F-2)2 22 x F2 = 30 x (F-2)2 22F2 = 30F2 - 120F + 120 8F2 - 120F +120 = 0 F2 - 15F + 15 = 0 F = (15 +/- sqrt(225 - 60))/2 F = ~1 or ~14, meaning F-2 = -1 or 12 The original document was font size 14, and it was shrunk to font size 12.
I actually got away with something like this a couple of times before clients wised up and realized that "page" doesn't mean anything in electronic publishing unless it's clearly defined.
You can also shorten the space between paragraphs and slightly change the margins. Not really noticeable and saves space. But I don't think this is the point that was being made.
How Much Weight Would The Boat Need To Have To Make This Possible?
Pretentious-Polymath:
Exactly enough so that it would sink when trying to use it the regular boating way. The buoancy in that setup is mass of displaced water minus mass of the boat. Volumes for boats can differ, but this should be around 2500 litres, so 2.5 tons of weight to stay underwater like that.
It's called "Willing suspension of disbelief". Blackadder: "I don't want anyone staring at my willie suspension in disbelief!"
"Exactly enough". No, less than that because the edges of the boat are underwater. Just rock the boat enough to let enough water inside to make the buoyancy less.
What Is The Area Of This Shape If The Side Length Is 4?
HAL9001-96: well first lets figure out what the shape is exactly then the rest is pretty easy more specifically what its proportions are if we take the angle of the extension in radians a, the radisu of the inner circle r and the sidelength l we know l=(2Pi-a)*r and l=a*(r+l) so a=l/(r+l) so l=(2Pi-l/(r+l))*r l=2Pir-lr/(r+l) lets set l=1 for now so 1=2Pir-r/(r+1) 1=(2Pir²+2Pir-r)/(r+1) 2Pir²+2Pir-r=r+1 2Pir²+2(Pi-1)r-1=0 quadratic equation solves to (1+root(1+Pi²)-Pi)/2Pi or about 0.1838742 whole thing scales proportionally so r=0.1838742l and a=1/1.1838742=0.844684 so total area is (0.1838742l)²*Pi*(2Pi-0.844684)/(2Pi)+(1.1838742l)²*0.844684Pi/(2Pi) or about 0.68387l² if l=4 that makes about 10.94
OK, this was believeable, right up to the word 'easy'. After that, not so much /s
doesn't say that. What's NOT said can be more important than what IS said. Ask any lawyer.
Load More Replies...Will This Work In Real Life?
ledocteur7: Short answer : yes, but it's more of like localised shredding than a clean cut.
Long answer : any sufficiently large amount of pressure can destroy stuff, no matter the fluid used, hydraulic leaks in industrial machinery are incredibly dangerous, and when moving fast enough, air acts basically the same way as any liquid. But air is very light, even when heavily compressed, and will get redirected in contact with pretty much anything, so rather than getting a clean slice, you're literally blowing things apart until they are in 2 pieces.
That's correct. Surprisingly, it depends on the thickness of the "really thick steel". For steel a metre thick of so, the airflow in the gap becomes laminar and the cut is clean. Most thick steel is more like 0.05 metres thick and the flow is turbulent so spreads in vee shape at the end of the crevice and pulverises the centre of the watermelon rather than cutting it cleanly.
How To Mathematically Proof That 3 Is A Smaller Number Than 10
(Not sure if this is the altitude of this sub or if it's too abstract so I better go on to another.)
Saw the post in the pic, smiled and wanted to go on, but suddenly I thought about the second part of the question.
I could come up with a popular explanation like "If I have 3 cookies, I can give fewer friends one than if I have 10 cookies". Or "I can eat longer a cookie a day with ten."
But all this explanation rely on the given/ teached/felt knowledge that 3 friends are less than 10 or 10 days are longer than 3.
How would you proof that 3 is smaller than 10 and vice versa?
PreguicaMan: Start from:
A number is smaller than it's successor (aBeing smaller is a transitive property (if a < b and b < c, then a < c )
Than we get:
3 < s(3)
3 < 4 < 5 < ... < 10
3 < 10
How Many Ways Are There To Shuffle A Deck?
52!
8.0658175170943900791e+67
52 cards, the first card in the deck can be any of the 52, the second can be any of the remaining 51 and so on. That is 52!
The statement is not absolutely guaranteed to be true, but that's how to bet your money.
It depends on what you count as "shuffling". Shuffling isn't perfectly random, and many decks will be in the same configuration when bought or after being sorted, increasing the chances of duplicate decks. Then you could also consider a cheated shuffle, which will also make more consistancy and greater chances of repeats
Load More Replies...I make that = 8 x 10^67. That's about the number of atoms AI estimates to be in the Milky Way galaxy - our 'home' galaxy. It's a lot.
Which One Is Correct? Comments Were Pretty Much Divided
I-am-the-Vern: If I imagine myself holding the scale from the ring end, I’d have to pull 100N to get the left weight suspended. If I replace my 100N exertion with a 100N counterweight, the scale won’t recognize the difference. That’s as simple as I can figure it.
I think it should read 100N but it’s kind of late at night so I’m probably not thinking straight though they did ask this question a few years ago in a national engineering exam
I've never seen a spring balance in kgf but I suppose there might be one, somewhere ...
Load More Replies...Wouldn’t You Just Stop At The Core Due To The Earths Gravity?
Terra_B:
No you will: Max out velocity only about 200km Probably hit a wall due to corolis effect / orbital mechanics Actually in the middle of the earth would be little gravity as there is equally as much mass above as below you
Ignoring the (sensible) effects of corolis, and assuming a vacuum so no resistance, and the fact that the Earth is actually liquid, you definitely would go through to the other side. You'd 'stop' at the other end, and start falling back, just like a thrown ball. Absolutely no idea of the speed, however, that's ridiculously complex because you're inside the object pulling you to the centre!
I Got 76, My Friend Got 80. Who Is Right?
CoolStuffSlickStuff:
84. There are 4 tiers on each side, each tier having 10 triangles. So that's 80. Then there are 4 wide triangles that span the left and right sides.
F**k, I had a math problem like this a while back. If I only could remember what I studied in P&C last week
What Would Be The Answer?
unatleticodemadrid:
It’s 042. Hint 4 rules out 7, 3, and 8. Hint 5 gives you that 0 is part of the code but is in position 1 or 2. Hint 3 tells you that 0 has to be in position 1 and another number is right so it’s 0x2, 02x, 0x6, or 06x. Using clues 1 and 2, you can deduce that 6 can be ruled out too since it doesn’t change position but it’s positioned right in clue 1 but wrong in clue 2. That’s impossible. So it’s only 0x2 or 02x. 8 has already been ruled out from hint 4, so that leaves 0x2 as the only possibility. Finally, from clue 2, we get 042.
It must be as it is the answer to the ultimate question of life, the universe and everything - Deep Thought
Street Hourly Capacity
VincentGrinn: the numbers are more or less right, 6k for busses per hour per lane is abit higher than i normally see but not by much
a lane of car traffic can move about 1,500 people per hour per lane, but traffic lights limit that significantly, 1100 might be an overestimate
walking is particularly hard to work out, some things ive seen say 15,000 per hour in a 3.5m wide space, but its rare to have so many people walking anyway
good street design definitely is just a matter of maths though
Now we just have to persuade two thirds of the population to leave their cars at home and cycle or take the bus instead. I vote we increase the tax on motor fuel tenfold and make public transport free. It might even save the planet.
Disagree with the last part of this statement because I live in a very small community and I have to drive a distance to get anywhere distance to do anything major like to do grocery shopping. Many other people live in small communities like me so this would affect them also. Not only that the price of everything else would go up to compensate for the higher taxes on gas. It is hard enough to live today with the prices are right now.
Load More Replies...we have these 'wonder' roads where I live. Bus traffic, maybe 500 people per hour, cyclists? Maybe 4. Pedestirans, less than 60 for sure.
Did I Do It Right?
Kees_Fratsen: 18 grams of -whatever- is always 18 grams
Were they asking for moles, molecules, litres etc but got confused with grams? Which d******d asked this question?
I tried extremely hard, but I can't make it more then 18 even by twisting semantics...
Why Wouldn't This Work?
kirihara_hibiki: Basically, it is true that the Limiting Shape of the curve really is a circle, and that the Limit of the Length of the curve really is 4. However, the Limit of the Length of the curve ≠ the Length of the Limiting Shape of the curve . There is in fact no reason to assume that. Thus the 4 in the false proof is in fact a completely different concept than π.
However, it is an excellent proof that pi is less than 4, should one ever be needed.
What Would Be The Volume Of 60,000,000 Pennies?
roge-: At 0.349 cm3 per penny, 60 million pennies would have an aggregate volume of 20.94 million cubic centimeters or 20,940 liters. As for how large of a container you would need to fit all of those pennies, its capacity would have to be greater than that, since discs won't pack perfectly.
Every part of that initial question and answer was stupid. This is NOT like the 'which weighs more, a pound of feathers or a pound of lead' question. This is 'do you want 10x the money or not'. The ONLY way this makes sense is if it was supposed to be 'do you want 600x $1 coins, or 60,000x pennies'. Otherwise, HOW the value is made available is irrelevant, one is 10x the other.
it says $600,000 in pennies which is over half a million dollars, if it said 600,000 pennies then it would be only $6,000. I would take the pennies and even with the 10% to convert at a coin star machine, i would do that.
If it were 600,000 pennies I'd still take that, put most of them in a sock, and just use it to get the $60k.
Now my question would be, if you took a large container and stack all those pennies in that container neatly or just randomly threw those pennies in the large container, would you need a larger container for the neatly stack pennies, or would you need a larger container for the randomly tossed pennies?
Is This Even Possible? How?
Angzt: Since the image shows 8 balls, I'm guessing it's the 8th that's also identical looking but actually heavier. To solve: Take two sets of three balls and weigh them against each other. Option 1: One side is heavier. Then pick two of the heavier side's balls to weigh against each other. Option 1.1: One ball is heavier. That's your pick. Option 1.2: Both balls weigh the same. Then the third one from the previous heavier set is the heavier one. Option 2: Both sets of three weigh the same. Then you weigh the remaining 2 against each other. One of them will be heavier and that's your pick. Oddly enough, you could do the same thing with 9 total balls and it would still work. The first weighing tells you which set of 3 has the heavier ball. Then you weigh two of those against each other and learn which one it is exactly.
The trick is really just that you separate into 3 sets, only 2 of which need to have identical numbers of items. In this way you identify one of three groups that contain the heavier item, instead of merely measuring half at a time (ie 2 groups). This makes it more efficient.
What's The Correct Answer?
mdroidd:
3.14^pi is slightly bigger than pi^3.14. It is tempting to generalise that to "higher power beats the higher base". However, numbers smaller than 2.718 (Euler's number) have the opposite effect. So in general, x^(x+dx) > (x+dx)^x when x > e. Proof: x^(x+dx) = (x+dx)^x Rewrite to: x^dx = ((x+dx)/x)^x Take logarithm of both sides: dx ln(x) = x ln(1+dx/x) Expand the right-hand side for small dx: dx ln(x) = dx ln(x) = 1 --> x = e
How Accurate Is This?
bassplaya13:
The defense budget is like $1 trillion. So 2% if that is $20 Billion. We have no idea how to construct such a large obsidian sphere, especially in the Sam Francisco bay. Obsidian is like $25 a kilogram, I’m gonna roughly guess that thing is 3km in diameter, which gives us 14.13 cubic kilometers or 14.13E+9 cubic meters. At 2250 kg/m3, that’s 31.8E+12 kg or 794 trillion dollars worth of obsidian. So it’s not even close from that standpoint.
But still, an obsidian sphere of any size would be a better investment than a bunch of USian stormtroopers
To What Extent Can Black Garbage Bags Actually Heat Up A Pool?
dietervdw:
Apparently the sun outputs about 1kW per square meter. Assuming the bag captures all of that and converts it into heat, that can heat a cubic meter of water 0,86 degrees Celsius per hour, or about 1.5F/hour. So seems plausible.
I have done similar with my pool. A black pipe leading from the output, round a concrete deck, and back in. Pool guy was impressed at the temperature increase. Another 'redneck' pool heater I used was a pipe leading to a copper coil in a firepit. Worked fine. I was going to to pump water to my shed roof through black sheets, but the cost of pumping is actually MORE than the cost of running a heat pump, so used a heat pump. Used all 3 and had warm (28C) water all winter in the tropics as low as 16C ambience in the daytime but sunny.
We can probably take 1 kW/m² on an area perpendicular to the rays of the sun. But only within the tropics is the sun directly overhead. The plastic bags will get warmer but lose some of their heat to the atmosphere by convection and radiation. The calculation is over-optimistic.
Is It Possible In Any Way To Either Prove Or Disprove It?
Nerves_Of_Silicon:
Proof by contradiction: *IF* 0/0 = 1. Then 2 * 0/0 = 2 * 1 On the left we can apply the 2 to the numerator (2 * a/b = 2a/b) so (2 * 0)/0 which equals 0/0. On the right 2 * 1 = 2. And that gives us 0/0 = 2 But we already said 0/0 =1 So now we have the result 1 = 2. Which is impossible. Therefore our original assumption must be wrong. And 0/0 does *not* = 1. By following the same logic, 0/0 can't have *any* definite value. Or else all of the maths we use immediately breaks down. So it doesn't.
Proof by definition. Definition 1: To divide by a number is to multiply by its reciprocal. Definition 2: The product of a number and its reciprocal always equals 1. Multiplication by 0 always yields 0, never 1, so 0 has no reciprocal. Therefore you can't divide by zero and why we say "Division by 0 is undefined".
Well, how about this in a no-zero number system: We know that .5 is 5/10 and we know that .3 is 3/10. So let's go to a base 12 number system with no zero and using T for twelve. Say that .6 is 6/T and .3 would be 3/T. With me so far? So doing this, we could extrapolate that all the numbers from .1 to .V (eleven) could be represented by 1/T to V/T. So what happens when we get to T? Well, we now have .T or we can say we have T/T which also equals 1. But if that's the case, then .T also =1 . And by further extrapolations, we have 1.T = 2, 2.T = 3, etc. Can we prove this? I don't know, but we can use this. Let's prove in a base twelve system that 1/2 is .6. Let's divide 1 by 2. We can't make 1 be a ten (besides that's a base 10 system) but we can change 1 into .T (see above). Now we have 2 going into .T (which is 2 going into 12) and we get .6 as an answer, which is 6/T which can be reduced to 1/2. So we know this works and I call these changeable numbers "walking numbers".
And any number divided by zero is infinity. Basically our understanding of mathematics does not cover this situation. As with infinity, zero (as something and not just as an absence of anything) isn't always a sensible concept in mathematics.
A number divided by zero tends toward infinity. (Infinity is a direction, not a number.) If y = 1/x, y gets very large as x gets very small. If you have one pizza, the smaller the slices you divide it into, the more people you can feed. (But don't expect them to come back to your next party.)
Load More Replies...What Is The Odds That This Has Happend In Human History?
MartinGallois:
The odds are so small that if everyone on earth was slapping a table every second since the beginning of civilization, the odds would still be almost zero.
I worked out that it was possible when I was about 11. Obviously I couldn't know the chances, but I knew it was non-zero.
I once randomly calculated the amount of pizzas you’d need to equal the mass of Venus which weighs 4.867 * 10^27g and assumed the average pizza weighed 300g. You’d need roughly 1.6*10^27 pizzas and if I further assumed each pizza had a standard diameter of 12.5cm and a thickness of roughly half an inch, the total volume of pizzas required would be roughly 4*10^23 m^3 which is about half the volume of Saturn
I love that there are mathematically talented people who are able to figure this stuff out because I could never. Need a decent paper written? That I can do, no AI needed.
I once randomly calculated the amount of pizzas you’d need to equal the mass of Venus which weighs 4.867 * 10^27g and assumed the average pizza weighed 300g. You’d need roughly 1.6*10^27 pizzas and if I further assumed each pizza had a standard diameter of 12.5cm and a thickness of roughly half an inch, the total volume of pizzas required would be roughly 4*10^23 m^3 which is about half the volume of Saturn
I love that there are mathematically talented people who are able to figure this stuff out because I could never. Need a decent paper written? That I can do, no AI needed.
