r/theydidthemath 1d ago

[Request] How many tennis balls are in this 1972(?) Volvo 145e?

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0 Upvotes

Presume that the car is filled to the brim of tennis balls.

Not sure exactly how helpful it may be, but the diameter for the tennis balls is somewhere between 2.575” and 2.7”. The dimensions of the car is 1.45m tall, 1.735m wide, and 4.64m deep. I don’t know the dimensions of the interior space. :-(


r/theydidthemath 1h ago

[Request] How many names on this list given the length?

Upvotes

r/theydidthemath 7h ago

[REQUEST] How long would it take for an average island to fall from sea level to the center of the Earth?

0 Upvotes

I was reading a fiction book (One Piece), and a certain situation that happens WAY LATE into the story intrigued me, and thinking about what could have happened led me to make this weird question.

If there was a hole big enough for the mass and area of an entire island (average) to fall through to the center of the Earth, considering drag in either water or air or magma, how long would it take? Because whenever I search it up, the quickest answer always discounts any resistance from any fluid at all, and example results that do take it into account wouldn't translate well into this particular question.


r/theydidthemath 17h ago

[Request] What are the chances of whitewashing in Battleship?

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0 Upvotes

r/theydidthemath 23h ago

[Request] Let’s try this one LAST time

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0 Upvotes

What is the % size?


r/theydidthemath 20h ago

[Request] What is the longest one could drive without changing lanes?

0 Upvotes

A job I had awhile ago had a fun part of the commute. On the way home, once I merged onto the highway, if I got into a specific lane, I could follow that line for about 15 miles. It would merge me onto the interstate and drop me off on the right exit without ever changing lanes.

I took that route again tonight after a date night and my mind mused…what would be the longest stretch in the world where you could get into a lane and never change lanes?

Rules:

  • No circles (e.g. multiple times around a roundabout)
  • Assume no construction or lane blockages/closures
  • A lane must be separated by painted lines, either dashed or solid. If a road ends to a non-painted street, that lane ends.
  • A lane change requires driving over a dotted or straight line. If the lane exits to a different road, but it continues in a single lane without merging lanes, that is allowed.

r/theydidthemath 5h ago

[Self] Why your $999 Apple MacBook Air is about to cost $1600

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909 Upvotes

Selling Price = (CoGS * (1 + Tariff%)) / (1 - Margin)


r/theydidthemath 9h ago

[Request] How far away could you see a space elevator from the Earth's surface?

0 Upvotes

As the title says.

Imagine you had some structure, like a tower or space elevator that extended into space, well beyond the atmosphere (ignoring the difficulties of creating such as structure).

If you were standing on the Earth's surface, and assuming relatively level terrain (we'll say approximately "at sea level"), how far away would you be able to be and still see at least a glimpse of this structure?

Bonus question (not really math, more optics/physics): What would the "top" of the tower look like at the point where you can no longer see it going up? Would it just kind of fade to a "vanishing point", have some clear cut-off, or basically fade as if someone put a transparent gradient at the top?

Thanks.


r/theydidthemath 4h ago

[Request] Saw this on twitter. I was thinking it was 2, but not sure.

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219 Upvotes

r/theydidthemath 7h ago

[Request] Did Pokémon accidentally reinvent the Monty Hall problem?

0 Upvotes

The Pokémon TCG Pocket game has a mechanic where you are shown 5 cards face down, in which there is usually only one desirable card, and let you pick one at random to keep

That's all well-and-good, but recently they added an event where you get to "peak" at one of the cards before you make your choice.

Now - if the one you peak is correct, you can just pick it, so that math ends there. However, if the card you pick is incorrect, does the logic of the Monty Hall problem apply?

I, and I think most others, mentally decide a card to pick before it's even time (I always pick the bottom right). If I reveal a different card and it's incorrect, is it statistically probable for me to forsake my mental guess and pick one of the other 3 cards? This feels wrong, the game didn't know that was my choice, it feels like it should now be no less likely than the other 3 cards.

However, wouldn't the logic of the Monty Hall problem apply to this, and say it is incorrect? That, logically speaking, my initial probability doesn't change from 1/5 despite the fact another one was eliminate (this is, to be clear, under the theoretical that the 'peaked' card is wrong, as the peaked card being correct ends the scenario). If there was a 1/5 chance my initial guess was correct, there is a 4/5 chance it was wrong. If a card is revealed, there is still a 4/5 chance I was initially wrong, but if there are only 3 possible cards to switch to, they split that 4/5 3-ways, making them each 26.66% likely to be correct (as opposed to my 20%), no?

This is my way of understanding the Monty Hall problem but practically speaking I don't feel like that can be incorrect? The game doesn't even know my initial 'mental' pick, so how could there be a statistical difference if I choose it or swap it.

And if any of the 3 swaps are really 26.66% likely in that scenario, wouldn't that mean mentally envisioning one and then swapping it is actually (very slightly) more likely than peaking at one at random and then picking one of the remaining 4 (25%)? Again, in both these scenarios just not factoring in the possibility that the peak is correct, which should apply to both scenarios equally anyway and not change the end result.

I don't know what the flaw in my logic is but I can't imagine that 26.66% correct. If the 1/5 chance the "peaked" card was incorrect is distributed to all 4 cards then it's 25%, but wouldn't that mean the Monty Hall problem results in a 50% chance instead of a 66% chance?

Can anyone help me break down the probability in this scenario? Is there a flaw in my understanding of the probabiltiy or do you really increase your chances by mentally choosing one and then refusing to take it?


r/theydidthemath 4h ago

[REQUEST] In Russia, Google LLC has 2 duodecillion debt. As I heard, even if we make exact copy of our planet made of 5000 rubles banknotes, it wouldn't be enough. Is it true?

0 Upvotes

Edit: 2 duodecillion in rubles. And also, it's debt only to TV channels, which I'm interested in.


r/theydidthemath 16h ago

[Request] What number can be expressed as a 1 with some amount of zeroes behind it that is larger than just 1 in the most possible numerical bases?

1 Upvotes

r/theydidthemath 19h ago

[Request] Would it be possible to calculate a rough estimate of the wattage of major supercomputers worldwide and how much they would heat the oceans if all off them were underwater?

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6 Upvotes

I'm talking about big servers like things used for chat got, YouTube, Facebook, crypto mining, etc.


r/theydidthemath 20h ago

[REQUEST] How long would it take to drive it back to Germany.. let’s say the center of Berlin using existing roadways from where it is today (Kubinka tank museum)

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4 Upvotes

r/theydidthemath 2h ago

[Request] Tower is 650 meters tall. It takes 7 seconds to form one regret. How many things can you regret if you fall?

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24 Upvotes

r/theydidthemath 16h ago

69 kilograms of computer storage would weight around 8600000000000000000 terabytes. [Self]

0 Upvotes

The weight of each bit is just one electron and one electron weight around 9.1*10-31.

(69kg)/((9.110-31)kg/electron)=7.581031 electrons

This is also the number of bits, to convert to bytes. We just divide by 8 and get

9.481030 bytes or 7.8 million yottabytes(8.61018 terabytes).

This is just an approximation and I was being generous in the calculations, please correct me if i got something wrong, it is very possible since I am just a child and English is not my first language.


r/theydidthemath 5h ago

[Request] what are the odds?

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0 Upvotes

r/theydidthemath 2h ago

[Request] 2 bullets hit each otherin center but one is way smaller? (see link)

0 Upvotes

Ye I know it's a movie but what will actually happen(hope you cna use links here):
https://www.youtube.com/shorts/EtS7FQZ4Lcg

way smaller bullet hit centrally bigger bullet (I assume they have same speed)


r/theydidthemath 12h ago

[Request] How fast is "385 bald eagle-hours per NYC to London"?

0 Upvotes

i'm assuming that they meant the flight time between the cities but can't do thing myself cuz i'm buzy laughing my butt off


r/theydidthemath 18h ago

[Request] Could 650 million people have visited the Kumbh festival in 45 days ?

0 Upvotes

In the recently concluded Kumbh Festival in India in 2025 it was said that almost 650 million people visited one place (City of Prayagraj) in 45 days.

Now the people came to the river banks, did the rituals and went back. some people stayed 1 night at the place. Some people stayed for 2 nights whereas a lot of people just came in the day and did not stay and went back the same day. There were some people who came stayed in the car and did not book hotels or stayed in open grounds

Is it possible that 650 million people visited in for 45 days? Is it possible logistically for transport, stay to manage this crowd

some sources of the info

https://en.wikipedia.org/wiki/2025_Prayag_Maha_Kumbh_Mela

This video gives an idea of the temp tent area where people stay

https://www.youtube.com/watch?v=kcxShS71QyQ

There are almost 100K tents build

https://www.moneycontrol.com/news/india/68-lakh-wooden-poles-100-km-fabric-and-3000-workers-making-of-tent-city-in-maha-kumbh-12907258.html


r/theydidthemath 11h ago

[REQUEST] How many FPM does Daredevil hear in the city? farts per minute.

0 Upvotes

Daredevil can hear a gun cock from blocks away.

Is he hearing hundreds of farts per minute all day long?


r/theydidthemath 10h ago

[REQUEST] Can skydivers in a wing suit fly up?

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388 Upvotes

I don’t mean like flapping their wings but - theoretically - could a wing suit skydiver find some perfect slope that works where they can gain altitude to a point of stall and land safely without a parachute? Alternatively could a glider do this?


r/theydidthemath 6h ago

[Request] how long this video is going to take

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2 Upvotes

r/theydidthemath 17h ago

[Request] How much would 12 French Francs from 1926 be worth in modern day Australian dollars?

2 Upvotes

I'm reading The Sun Also Rises, and its mentioned that the whiskey and soda the characters but from a bar costs 12 francs. Would that have been a lot of money? Not quite a straightforward currency conversion as both France and Australia use different currencies than they did when the book was written.


r/theydidthemath 17h ago

[Request] - How big would the crater be?

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191 Upvotes

Are we talking an extinction level event end of the dinosaurs type explosion? How much energy is released?