35 Times People Actually ‘Did The Math’ And Found Out These Interesting Things (New Posts)
Just like there are cat people and dog people, so there are math people and... all the rest of the population.
You see, while we, the mortal ones, still dread the memory of a cursed math exam which ruined our final semester back in high school and shattered our dreams, self-esteem, and carefree summer vacation ahead, some find great comfort in numbers.
If you’re one of them, looking for a space to flex your math muscle, you came to the right place. Welcome to the They Did The Math subreddit where 944k took ‘do the math’ literally and came up with very interesting results. “Useless yet interesting calculations,” states the community’s description and who doesn’t like arguments proven by the power of determination and careful mathematical calculation?
Scroll down, upvote your favorite posts, and be sure to check out our previous post with more examples of people and numbers being best friends.
Pretty Solid Plan!!
Can Someone Confirm Its True?
"Oxfam international said that... I don't know the exact figures but simple logic dictates that it certainly can easily be true. Think about it, most people in the world are poor, which means they have little to no net worth.
If Bezos has a net worth of 200 billion and each of these 4 billion people have 50 dollars in net worth, then you're already there. 50 dollars in net worth is not an outrageous number given that many Americans have negative net worth and little to no savings to speak of.
I don't know how much the top 8 are worth, but let's say it's 1 trillion. That means that the 4 billion are worth 250 dollars. Yeah that's plausible.
By the way even if you make 100,000 a year in the US you can have a net worth of 0 or negative net worth depending on what your savings/investments and liabilities are, which is often the case."
While a small fraction of society enjoys numbers just as much if not more than writers love books, most of us, some secretly, some not, are somewhat scared of this discipline. In fact, there’s even a whole term for it named ‘math anxiety’ and it describes people who experience feelings of stress when faced with math-related situations.
Moreover, it has some real-life consequences. Math anxiety (MA) has been suggested to decrease the math performance of students. The research has found that MA has a direct, negative influence on students' performance and that this negative link between the two was strongest among senior high school students. It was particularly strong among studies using custom tests and studies that assessed problem-solving skills.
I Stumbled On This Post And I’m Wondering If This Is True! Any Ideas ?
"According to the source it says it would take $20B to eliminate homelessness
The most expensive US aircraft carrier is $12.8B. So it's about 7.2B short. However, this is only the cost to build it, and excluded operational costs."
Math Lead Them To This Conclusion
"Lead can also be created directly in supernova explosions. It doesn't have to originate from nuclear decay."
How Much Memory Could Be Stored Today In The Same Volume As The Image On The Left?
"A micro SD card has a volume of 165 mm3. I estimate that box to be 8'x3'x20'.. This comes out to around 82 million SD cards, assuming a 100% packing efficiency. At 1TB per card that would come out to 82 Exobytes. .
It's hard to find a reliable estimate of the total data on the internet, but this website says 44 zettabytes, which means our box contains about 0.2% of the internet. Storing the whole internet on 1TB SD cards would take around 7300 m3, equivalent to a cube about 20m per side or 3 Olympic swimming pools"
So in order to find out where this belief that math is the most difficult science nut to crack out there comes from, we spoke with Dan Meyer, the Chief Academic Officer at Desmos, exploring the future of math, technology, and learning. Dan has been advocating for better math instruction here and on CNN, Good Morning America, etc. and he was named one of Tech & Learning’s 30 Leaders of the Future.
“Students often come to believe that math is strictly about getting right and wrong answers to problems about calculations, that there are many ways to be wrong and only one way to be right,” he said. However, “math, as it's practiced by mathematicians, by professionals, and by people across cultures, often emphasizes experimentation, play, coming up with an idea, testing it out, and improving it,” Dan explained.
What Would The Price Difference Equate To? How Would Preparation Time And Labor Influence The Cost?
"I think we have to work this out at UK prices, because, as people have pointed out, that's a £3 tesco meal deal on the left, with a starbucks drink and a pastry. Also, we need to compare like with like, and US and UK food prices are vastly different.
As the meal deal items are from tesco, we can get the nutritional info from the website, which is important for working out the price.
The Salt and Vinegar McCoys are 251KCal, coke is 210KCal, and the sandwich looks closest to their chicken bacon and stuffing sandwiches, which is 483KCal. That's 944 KCal, so the other two items should add up to around 656KCal.
As three items are from tesco, I'm going to guess the other two are from the same store and that's a butter croissant from starbucks, at 259KCal costing £1.19 if you eat out, which I'm guessing is the situation as they've been taken away for this photo.
That means the drink is something from starbucks with 397KCal. A 500ml coke bottle is 23.5cm high, so that looks like a 18cm tall starbucks cup, maybe 16cm without the lid. A venti cup is a little over 15cm tall, which means that's a venti.
There actually is a venti drink from Starbucks with a calorie count of 397, which is a hot chocolate with whole milk, and as that's £2.65 to go, that brings the left hand total to £6.84.
That's the easy part.
Now the right hand side. Reverse image search on the cropped right hand side didn't show anything up, so doing it the hard way, we have avocado on ryvita, mixed berries, yoghurt with mixed berries, Looks like spinach on two of the plates, kale on two, yoghurt, broccoli, cauliflower, tomato, and then it is a bit more guess-y. Top right plate has some sort of grain, maybe rice, maybe bulgar wheat or somthing. There's also something spreadable, I'm guessing houmous. I'd guess that's bulgar wheat with bell peppers, houmous with a little paprika on top, and kale.
The plate of mixed berries in the middle towards the top just looks like strawberries and blueberries.
Left hand side middle looks like yoghurt with chia seeds sprinkled on, wilted spinach, and something red which looks tomato based, so maybe a salsa? I could be way off and it could be a mashed root veg like carrot or sweet potato also, but I think I see a little liquid from it at the lower end where it meets the spinach, so I'm going with a mild salsa.
On the middle right, there's broccoli and cauliflower, kale and something red, which I think is tomato, but may possibly be bell pepper? The other item is a little harder, but I think that's a baked potato with tuna filling.
Bottom left plate is wilted spinach again, tomato, and some sort of mushroom dish. Looks like there's kale, tomato, and something else in there. Maybe cauliflower, but very possibly a bunch of ingredients you can't tell at that resolution and just from a picture.
Bottom right is just yoghurt with more strawberries and blueberries.
Now for pricing. I'll get the prices off tesco, but lots of this stuff is seasonal, so it'll vary through the year. Note that UK food prices are lower, 'cause last time I did this, no-one believed we pay so little for food. You can check the prices at tesco.com if you use a vpn or something to pretend you're in the UK.
Ryvita - get the off brand ones for 69p. About 28 per pack, so 5p for the ones shown. I'll do all the pricing like that as you could divide the food amongst multiple meals or multiple people.
Avocado, 75p. I'm going to say that's a whole avocado in the image.
Bulgar wheat, 500g for £1.15, so let's say 75g, costing about 17p.
Bell pepper, 86p for 3, so probably 28p for one will get you enough bell pepper for all the stuff in the picture.
Houmous, £1.10. You can make it yourself for less, but that's a bit OTT for this calculation.
Regular kale is out of stock when I searched, which is fine, as whenever you do this you'll find some stuff is more expensive, so it'll even out. That means buying the expensive kale, at 1.5 for 200g, which will do all the kale in the picture.
Let's make sure to include the paprika, which is 90p for 52g which can mostly sit in your cupboard, so let's add 2p in paprika.
Strawberries - £1.39 for 227g, enough for the whole image.
Blueberries - 89p for 125g, again enough for every dish.
Mild salsa - 80p
spinach - 900g for £1.50. Given how much this stuff shrinks as you cook it, even if you could split it over more than one day, I'll play it safe and just say that's for this set of meals.
Chia seeds are £1 for 150g, so that's maybe a 5p sprinkle at most.
Yoghurt - 75p for 500g, which also means we now have everything for the bottom right dish.
One big spud - 25p
tuna - £1.20 frozen bag of cauliflower and broccoli mix is 89p for 900g, so that's 25p in broccoli/cauliflower at most.
We already have the kale and pepper
One tomato - 15p
two mushrooms - 12p
We probably already have the other ingredients, but let's add in a little more in case there's something significant missed for that recipe. Based on the existing prices, I'll add in another 10p for a possible mystery ingredient.
That gives us a total of £11.32 for the stuff on the right, vs £6.84 for the stuff on the left.
Labour time will influence the cost, but all the actual meals on the right are super quick to prepare. The worst might be the potato, but even then it's about a minute to prepare it, then you just leave it in the oven and come back. All the meals have suprisingly low prep time."
Is This True?
"The video I just saw showed that they spent about 5 minutes naming the victims of 9/11, of which there were 2997 victims. Johns Hopkins has the USA at 463,437. All you need to do is set up a ratio.
5 minutes / 2997 deaths = x minutes / 463437 deaths
463437 * 5 / 2997 = x
x = 773.1681681681681681681681681681...
Which works out to 12 hours 53 minutes 10.09 seconds"
Why Can’t People Do Math Properly? Recalculate!
"The only error here is the rounding in 4 weeks per month. There's actually around 365.24 / 12 / 7 =~ 4.348 weeks in a month.
So you'd make $5,000 * 4.348 = $21,740 per month and $21,740 * 12 = $260,880 per year.
That means it'd take you $1,000,000,000 / $260,880 =~ 3,833 years to get to a billion dollars.
Yeah, it's a bit off from what they got but it illustrates the point just as well.
All the other maths is correct."
He also noted that it's the math students need right now. When asked how you teach children to be interested in mathematics so they don't dread it as they turn into adults, Dan had a couple of suggestions. “Ask questions that offer students opportunities to draw on their senses and their intuition, questions that have lots of possible answers, where even the wrong answers are interesting.”
He continued: “For example, show students a pattern of shapes that's growing predictably. Ask them what they notice about the pattern? What do they wonder? How long they think it'll take the pattern to reach a certain size? And only then help them with their calculations.”
In Soviet Russia, Coffee Is Served At A Ridiculous Pace
"For anyone wanting context, Stakhanov was a common caricature for a while in soviet culture (based on a real person), about people who go way above and beyond in their job. Like a chuck norris, but for manual labor.
It started out serious (the real person apparently hauled 100 tons of coal in 6 hours), and he was promoted as a person to be emulated. But the tales got more and more outlandish as time went on, as people got disillusioned with the whole idea"
Does Zuckerberg Hold 2% Of All Millennial Wealth?
"Millenials own 5000B wealth, per this:
Zuckerberg owns 111B of it, per this:
How True Is This???
"Jeff Bezos net worth: $181,200,000,000
Baltimore average net worth: $555,423
Baltimore median net worth: $255,000
Baltimore population: 593,490
Total net worth (without Bezos): $329,637,996,270
Total net worth (with Bezos): $510,837,996,270
Average net worth, with Jeff Bezos: $860,735.
(I assume the median would remain at $255,000)"
In 100 M Of Space, How Many More Bricks Would A Regular Straight Fence Have?
"As you can see in the picture it's a very thin wall, looks to be 1 brick thick. A straight wall only has support on one axis and would need to be at least a few bricks thick to stay standing. The curved wall allows more support in multiple axis allowing the use of less bricks."
If You Blended All 7.88 Billion People On Earth Into A Fine Goo (Density Of A Human = 985 Kg/M3, Average Human Body Mass = 62 Kg), You Would End Up With A Sphere Of Human Goo Just Under 1 Km Wide. I Made A Visualization Of How That Would Look Like In The Middle Of Central Park In NYC
How Much Money Would It Be If The U.s Government Did This?
"First source I found shows FY2020 military budget is $714B, so cutting 25% would be $178.5B. I think that's a conservative number, considering that they may have gone over budget and it'll likely increase going forward.
A very simple look at wealth tax would be looking at total net worth of millionaires or billionaires in the US. Not able to find a distinct number for millionaires, but I see that the 660 billionaires in the US have a total wealth of $4.1T. 1% of that is $41B."
Is This Really The Price Difference In Wood Between January 2020 And June 2021?
"For what it's worth, I live in the pacific northwest - timber country - and the price of wood has gone up over 100%. Elsewhere I know it's more. I have been harvesting fallen trees in the woods for projects lately. The complication with this question is that the prices have inflated different amounts in different places . So this could be correct where the photo was taken."
How Many Bees ?
"Some additional math:
- 10k bees weigh about 3 pounds, so 6.3M bees is about 1900 lbs. No problem for the car.
- 1/2 cup of bees (0.00418 cu ft) = 300 bees. Using that with a 141.3 cu ft interior results in 10.1 million bees.
- 30k-60k bees need 2 deep boxes for a hive (3.33 cu/ft). So if you wanted the bees to build a hive in the Lexus, there would only be room for 1.2-2.4 million bees.
Any way you do the math, it's the same order of magnitude."
Big Ooof If True. I Checked The Link And The Numbers Did Make Sense. Can Someone Double Check With Me?
"So the US spent $718.69 billion on military stuff last year. So 3% of that is $21.560 Billion. Using the stats from this website:
You’d have to be able to feed each of the ~820 million critically hungry people on $26.29 each- for a whole year. maybe feasible in some countries, since the US dollar can be pretty strong, but definitely not in most.
Granted, the sign could be suggesting an investment in infrastructure to make food cheaper for everyone. But on the face of things, you could probably end world hunger for maybe six meals"
Could Jeff Bezos Really Give All Amazon Employees $105k And Still Be As Rich As He Was Before The Pandemic?
"It’s complicated. Maybe calculated as his net-worth that’s probably true, but you need to understand that he hasn’t that money just lying around.. most of his wealth is bound as amazon stock. He can’t just take money and give it someone else. And if he‘d give away amazon stock, it would probably crash the stock market and would be guilty for market manipulation, regulations are pretty strict on that.
Yes, he should definitely do much more for amazon employees, but assuming he can just hand out sh*tloads if money doesn’t reflect reality."
How Many Km Of Rna Is Needed To Vaccinate The Entire World?
Can Someone Check The Conversion Rate And Inflation On This One? Merry Christmas!
"According to the Wikipedia arcticle for bob cratchit 15 shilling per week back then amounts to £36 or $54 US per week in 2015. With 52 weeks in a year (actual 1843 week count), that amoungs to $54*52=$2,808. The statement in the Post is incorrect."
Making Water At Home Is Something You Might Not Want To Be Home For. Or Have A Home After
"a. Isn’t this basically rocket fuel and b. I’m pretty sure they do this in the Martian if you’ve seen the movie. otherwise cool calculations"
Hey Google, How Many Days Since July 4th, 1776?
Is This Accurate With How Much Their Tax Is? Or Is This Hooey?
"That just looks like a 3% tax. If that's what you're talking about, then it's accurate.
To do the math, take the "leave them with" amount, add back in the "would owe" amount, and you have the amount they're starting with. Multiply that by .03 and you get the "would owe" amount again."
Aside From The Meme, Is This True?
"The conversion formulas are:
SPL = 20 * log10( p / p_0 )
p = p_0 * 10 ^ ( SPL / 20 )
With p_0 = 2e-5 Pa and 194 dB you get 100 kPa or 1 atm. After that point a sound isn’t really a sound but more of a shock wave, and it’s not clear how meaningful dB measurements are.
At 1100 dB you get a pressure of 2e50 Pa. Pressure isn’t really the right way to measure a black hole because size is also very important. But for reference, a Neutron Star, where atomic structure has collapsed, can have a pressure on the order of 1034 Pa. So 1050 Pa sounds like enough to me."
Is This Why It's So Hard To Buy A House These Days?
"Now, there are issues with this, because we aren't weighing population growth and decline in these cities (rust belt population, demographic collapse of certain cities such as Detroit, etc.,). I think they just took "average price in X city." Back then there wasn't the insane income inequality from city-to-city either, so that factors. (e.g., median wage in a city that would go on to form the Rust Belt back then was closer to that of the coastal cities. Now you can famously buy houses in ghettos where there are no jobs for very little money- but you have no municipal services, among other issues.)
I genuinely think they just "averaged" these cities out by 'large municipal area.' I can't factor for wage growth in areas like Silicon Valley. We've seen extreme bifurcation in value and wages in these localities since 1971.
So, I instead took just my nearest city I lived in, Philadelphia. It's a sort of "normal" city that isn't an outlier (it's not exactly Detroit, nor San Francisco, but 'somewhere in-between.') So I'll use it as a yardstick, because I'm not spending more than like, 5 minutes on this thing, and hell, someone's gotta actually take a swing at this.
In 1971 a home in Philadelphia was 14,800, or in today's dollars, just a hair under $100,000.. For today, however, in that same municipality, it is $280,000., with the data ending in June and showing zero signs of slowing if you look at the chart's rising tail.
For everyone saying "but it doesn't have modern amenities-" I don't think anyone buying a "starter home" cares if it was built in the 1800s, 1900s, 1950s, 1970s, or today. Most want a place to build equity where they can stop burning their cash on rent and start putting it toward saving, maybe move up to a better home later once they have the equity.
Most places are at least wired for some kind of broadband. Most places have electrical outlets that meet code.
Past that, you can run either a window unit or space heater if you really have to, with the other differences being so small as to not matter, (at least when it comes to starter homes. It's not like it's a smart home that's hyper-modern.)
Starter homes of a modest size aren't really built anymore- and there's a reason for that. But for people 'starting out' in homeowning, it looks like the last few years and some change just made that a lot harder."
I Saw This On R/Memes And Was Wondering How Far This Will Take Us From The Sun By The Time It Swallows Earth
"There's a paper published that calculates what fate the Earth suffers due to the sun swelling into a red giant. I'll see if I can find it.
Here it is:. https://scholar.google.com/scholar?hl=en&as_sdt=0,5&qsp=1&q=fate+of+earth+sun&qst=ib#d=gs_qabs&u=%23p%3Dqw-giyuR1AMJ
Anything inside 1.15au currently is doomed.
To elaborate: the sun will likely puff up to red giant with a diameter encompassing Mars. Which suggests that Earth will definitely be engulfed. That simple model however neglects that the sun will have lost a significant amount of mass by then which would tend to cause the orbits of the planets to expand. The paper calculates that even given the mass loss the Earth is still doomed."
Scott Manley Did The Math
"Couple issues with this post.... 1) it’s not downloadable on Steam 2) Ark: Survival Evolved is much larger with dlc involved."
Is This Correct? And How Much Power Could That Generate?
"That 5.5% figure is very clearly bullshit.
The mainland US covers 3,119,885 mi2. 5.5% of that are
3,119,885 mi2 * 0.055 =~ 171,593 mi2.
There are a bit less than 300 million motor vehicles in the US, but let's use that number to highball (note: that would include Alaska and Hawaii while our area claculation does not).
That makes for
171,593 mi2 / 300,000,000 =~ 0.000572 mi2 =~ 15,946 ft2
of parking lot per vehicle in the US.
A large pickup truck might be 20ft long and 7ft for a total of 140 ft2.
Let's say we need parking space just over 4 times that size per vehicle, so 500 ft2.
That would mean there were enough parking lots to park every US vehicle
15,946 ft2 / 500 ft2 =~ 32 times.
And that is, without a doubt, bullshit.
Especially considering that we're ignoring parking space on the side of roads and individual parking spots on people's private property.
So where the heck does this number come from?
I'm guessing it's this article which states:
In all, the model estimates that about 5.5% of all U.S. land was covered by parking lots in 2012
Huh. But then, under a picture it has the following:
About 5.5% of developed land in the lower 48 U.S. states is covered by impervious parking lots [...]
They conflate "all U.S. land" with "developed land in the lower 48 U.S. states". That's two very different things.
So what does the actual study say? At least they link to it (might take a while to load) which is more than most such articles do.
But looking at the brief summary, there is no mention of 5.5%. Some other, more specific figures, but no overall value for all developed land or even all land. It does clarify that they're only going for the conterminous 48 states, though.
So let's dig deeper. The first linked file has their metadata which also summarizes all their findings. Still no 5.5% though.
What is in there, is this snippet:
This was 5.46%, compared to the true parking areas in the validation areas, which was 5.49%.
That's the only source of a 5.5%-ish figure in there.
So what's the context? Well, this is under the section "Process Description". Notice the term "validation areas"? Those are the areas they ran their automated measuring tool (classifying parking lots from satellite data) on for which they had actual data, so that they could compare and ensure that their tool provides good results.
What was that validation data? It's listed as the following:
Bloomington, Indiana; Chattanooga, Tennessee; Denver, Colorado; Hartford, Connecticut; Wake County, North Carolina (city of Raleigh), and Ramsey County, Minnesota (St Paul)
So, 6 cities. That's where the 5.5% comes from. These 6 cities are 5.5% parking lots.
Nothing else. The study does not give a total for the entire US (or 48 states). It doesn't give a total for all "developed land" either. It has sub-categories of this with data but without knowledge of their proportion to each other, we can't derive an overall value here.
Whoever wrote that article, do better.
But sure, let's cover 5.5% of the mainland US in solar panels.
That's 171,593 mi2 as we calculated earlier.
Solar panels might average around 6 kwh per square metre per day.
171,593 mi2 =~ 4.4443 * 1011 m2.
4.4443 * 1011 m2 * 6 kwh/(m2*day) = 2.66658 * 1012 kwh/day.
The US uses about 3.8 * 1012 kwh/day. So we could cover a solid 70% of that with our solar panels."
So About How Many Extra Nuggets Would That Be?
"Let's assume that this is part time worker. We can't say for certain how many hours they would get in a given week, so we will assume that they work 20 hours per week.
It was stated that they worked at McDonald's for 2.5 years. With 52 weeks per year, this would give us a total of 130 weeks (52 x 2.5 = 130).
At 20 hours per week, for 130 weeks, we have a total of 2,600 hours worked (20 x 130 = 2,600).
The remaining variable is how many orders of 10 piece nuggets occur each hour. Each order represents 1 free nugget. There are many factors which determine how many orders there are per hour:
-The number of 10 piece nuggets ordered would be higher during peak dining hours, and lower during off peak hours.
-Nuggets aren't served during breakfast hours.
-Location would have a major impact on this number. We would expect a location in a densely populated area to have lots of customers (and therefore more orders of 10 pice nuggets each hour). We could assume that a store in a more remote location would experience a smaller number of customers.
For simplicity, let's assume that there are 10 orders of 10 piece nuggets per hour.
With the assumptions above, we have the employee working for 2,600 hours, giving away 10 free nuggets in each of those hours.
2,600 hours x 10 free nuggets per hour = 26,000 free nuggets"
Just Saw This Meme And It Seems Wildly Out Of Proportion. Can Someone Confirm Or Give Me A More Accurate Number To Share With My Buddies?
"Golf courses are between 5000-7000+m long on average on the card plus extra walking and the fact that unless you are pro you arent going in a straight line the whole time you can do nearly the same again.
Assuming 6 mile (9.6km) walked per round, 1 round per week minus 2 for holidays that would give 50*6 or 300 miles.
Assuming one has a pint at the end of each round, that would give 50 pints or 6.25 gallons
My math says that that equals 48mpg
So the numbers look like they are assuming 3 rounds a week but the ratio is there or there abouts"
How Long Till The Average Person Farts 500k Times
"The average person farts between 5-15 times a day, using the median (10) it would take 50000 days to fart 500k times. This is 136.9863 years."
How Long Could An Average Car Stay On Before Running Out Of Gas?
"The average car is a Toyota Corolla which has a gas tank big enough to hold 13.2 gallons of gas. An average car uses about 1/5 of a gallon of gas an hour if you let it idle. 13.2÷.2 is 66. So about 66 hours in a full tank. I did a whole 5 minutes of research on this and I don't know if I used the right equation so I may be wrong"
Note: this post originally had 55 images. It’s been shortened to the top 35 images based on user votes.