/r/theydidthemath

Photograph via snooOG

And they said math has no real world applications

Submission Rules

  1. Proper title tags are required for all posts or it will be removed! The tags accepted are at the end of the sidebar down there.

  2. State clearly what is being or what you want calculated in the title. [Request] posts must have a calculable answer; otherwise, they will be removed.

  3. Give credit where credit is due—include the user who made the calculations in any post you submit: ex. "[RDTM] /u/FragTheWhale calculates...".

  4. For easy and quick math results (ex. How many feet are in a mile?) use Wolfram|Alpha™. Posts containing "simple math" will be removed, as well as requests whose answers are easily searchable online, and any other post at the moderators' discretion. For more abstract math, try /r/math or /r/learnmath.

  5. Posts which seem to be asking for help on homework will be removed. Try /r/homeworkhelp or /r/cheatatmathhomework instead.

Comment Rules

  1. This subreddit has a zero-tolerance policy for hateful or unnecessary language. There is no warning for hate speech of any kind. Rule breaking posts/comments will have a temporary ban that will serve as a first offense "warning". Repeat or egregious offenders will be banned permanently. Reddit's site-wide rules still apply here. Also, don't be a dick.

  2. Do not submit top-level comments in [Request] posts that are not an attempt at an answer or a request for clarification. Jokes or off-topic top-level comments will be removed.

  3. When answering [Request] posts, please cite reputable sources to defend any evidence that cannot be proven using your own math.

Report any spam/rule breaking posts to the mods with the report button. Be sure to include the reason for your report!


LaTeX and subscripts/superscripts

[; e^{\pi i} + 1 = 0 ;]

Superscripts and subscripts are supported in this subreddit, and LaTeX is used here as well. If the above equation looks like garbled code, or for information on how to display subscripts and superscripts, check our wiki page.


Our Friends & Partner Subreddits:


TAGS!

We require title tags. Here are the tags we accept and what they are for. Please keep them at the start of your post.

  • [Request] - Asking the /r/theydidthemath community to do the math for you!

  • [Self] - You did the math and want to share it!

  • [RDTM] - "Reddit Did The Math", linking to a comment or post on Reddit where someone else does the math!

  • [Off-Site] - Use when linking to any site, including Imgur, that is not reddit.com.

  • [Meta] - Non-math posts regarding the subreddit itself. Don't use this unless you really have to.


Sidebar image from Randall Monroe's xkcd

  1. Browse by tag ▸
  2. Request
  3. Non-Request
  4. Self
  5. RDTM
  6. Off-Site

/r/theydidthemath

1,467,251 Subscribers

0

[Request] [Spoiler for Death's End, Three-Body Problem 3rd book]

So, on the 3rd book, some ultra-advanced aliens use a dimension-shattering weapon on the solar system, reducing it to 2 dimensions. How much (more) area would the solar system use if it was smashed to a 1 atom thick sheet? Would it be bigger than the current plane where the planets orbit?

1 Comment
2024/03/29
22:59 UTC

0

[REQUEST] How fast would a person have to run to make their shoes catch on fire?

I saw this post and it made me curious

1 Comment
2024/03/29
22:20 UTC

88

[Request] What happened?

If you need numbers, it was an 100 meter sprint and 1st place(the person in the video) ran it in 9.87 seconds. It didn’t provide anything else.

10 Comments
2024/03/29
21:33 UTC

1

[Request] Hypothetically how long would it take to walk from Romania to Spain?

Lets say from Bucharest to Madrid. Im just rly curious

9 Comments
2024/03/29
19:49 UTC

0

[Request] How to divide buy 2 get 1 equally?

How to divide buy 2 get 1 free equally with different prices?

Assuming there’s a buy 2 get 1 free offer. 3 people went and bought 3 items together, each had a different price. The prices were 500, 300 and 200. The 200 one is counted as free, so the total is 800. How much does each owe?

6 Comments
2024/03/29
19:48 UTC

1

[Request] Optimal angle for partially obstructed solar panel

I have a small solar panel that powers a bird feeder camera. The camera is mounted on a N/S running fence and the panel will be mounted on the same. The fence is public-facing, so I don't want to mount the panel on the top of the fence to deter theft/vandalism, so the panel is obscured from sunlight for about half of the day.

Under these conditions, what is the optimal E/W angle for best performance? I can see two intuitive solutions: A) mount the panel as normal, level in E/W direction and N/S by latitude, for optimal noon-time performance; and B) mount the panel at an angle midway between daylight the exposed daylight hours for optimal exposure to full daylight range. Lets assume a latitude of 40° if necessary. Likewise assume an obstruction from 0-80° on the sunrise side.

I can see an obvious case for B, but also can imagine the case for A in accounting for diminished solar brightness as it sets.

I'm aware that it likely doesn't matter for such a small application, but I'm still interested in the answer conceptually.

3 Comments
2024/03/29
18:30 UTC

6

[Request] can i, a 25 year old man, watch a new movie every day until the day i die? assuming i've never watched one before.

21 Comments
2024/03/29
17:13 UTC

6

[Request] Is printer ink more valuable than blood?

My friend joked that printer ink was more valuable than gasoline, but I couldn't find any value for blood, crude oil, and other expensive fluids. Could you find and compare the values for those? I need to find out whether printing with blood is economical...

8 Comments
2024/03/29
17:07 UTC

0

[Request] How much energy would be needed to create cubic meter of space?

As the title says, I am trying to figure out how feasible it would be for some sort of imaginary machine to create new space where none already exists, and in some sort of place that the expansion of the universe wouldn’t already reach. I’ve done some research into dark energy and from what I can tell, dark energy would only accelerate the rate of expansion, and any amount of space would expand infinitely under its own momentum given that it could overcome gravity.

2 Comments
2024/03/29
16:19 UTC

516

[Off-Site] How much is a word worth?

14 Comments
2024/03/29
16:09 UTC

3

[Request] How to find the perfect speed when raining ?

Hi, i have always been asking myself this question : what is the ideal speed to have the littlest amount of rain droplets possible with a same length traveled when walking or running. I think a function could do the job to find this. I know a too much small speed means more droplets, but a bigger speed means more droplets too. I do no know how to find such an equation and how to think about this. It seems so simple and hard at the same time. I tried to ask Chat Gpt but he could not really answer this, so I have to try this math community.

Please, i want an answer to one of my biggest life questions 😭!

12 Comments
2024/03/29
15:16 UTC

3

[Request] Is this possible?

How much strength are Jack Sparrow and Turner exerting?
How much oxygen time do they have?

https://preview.redd.it/f8cxyghtgarc1.jpg?width=671&format=pjpg&auto=webp&s=8f81f8093aec5960d035c95874bcc8812d07a61e

3 Comments
2024/03/29
15:09 UTC

643

[OFF-SITE] on this geeky anarchist graffiti, they did the math

9 Comments
2024/03/29
14:19 UTC

30

[Off-Site] Post nut calculations.

6 Comments
2024/03/29
13:14 UTC

1

[REQUEST] (Re)Caculate the plausible energy (in kilowatts) being use to make an single 12-hours Anime style digital art made by an average male artist live inside an average appartment.

Here is the link to the comment. I tried my best to make the math but it only took 2 hours with only a very very basic math and physic understanding. I hope you guys can correct my result.

https://preview.redd.it/pca3xivzr9rc1.png?width=796&format=png&auto=webp&s=e12a8283cc60ed514af07ebc178d18db30aaaf86

3 Comments
2024/03/29
12:49 UTC

2,121

[SELF] TISSUE MATH

32 Comments
2024/03/29
12:36 UTC

1

[Request] Is it possible to figure out how much of the internet one has seen?

The entirety of the internet was 175 zetabytes in 2022 according to Quora, and "only" 64 zetabytes in 2020. The internet is huge. But is it possible to figure out an approximationof how much of the internet one has seen? A part of me doubts that it's even calculable, but I'm asking in case anyone could make an educated guess.

2 Comments
2024/03/29
11:32 UTC

6,855

[Request] My GF Ring size

I managed to trick my GF into sending me this photo of her hand with a 2p coin on it, can anyone please work out her ring size for her ring finger please? We're going away and I'm planning on proposing to her.

697 Comments
2024/03/29
10:57 UTC

3

[Request] How many variables can my calculator use?

I play around with programming a TI-92+ graphing calculator. With the TI Basic programming language, I can use variables for subroutines, program names, folder names, and variables in math functions. A variable can consist of most combinations of lower case letters and numbers of up to 8 characters with a few exceptions. A variable cannot be a number, or start with a number. Upper case letters are ignored and are assumed to be lower case. There are a few locked variables or system variables that cannot be used, but we'll ignore those for this query. A variable can only consist of letters and numbers and cannot exceed 8 characters. There are are Greek letters like theta, I can use, but we'll ignore those too and just stick with combinations of the standard English alphabet and numbers.

Examples of valid variables:

prog1 begin begin1 x counter folder3 startval v12342 value6 date4

Examples of invalid variables:

5folder - begins with a number

folder6717 - exceeds 8 characters

folder.x - contains an invalid character. No spaces or symbols can be used.

A variable containing a capital letter like dateWeek would be the same as dateweek and not to be included.

Assuming these rules and exceptions, how many variables can be used? Thanks!

3 Comments
2024/03/29
10:19 UTC

14

[Request] If we gave everyone on Earth an equal sized piece of land (not counting children), how much would we each get?

Not sure if the data on how many minors there are is obtainable, but I figure as long as the land is big enough for a house (especially if two adults combined their land to make spawn together) they'd live with them until adulthood.

I don't want to make this harder than it already seems, so let's just assume anything above water is good, farmable, liveable land for this lol

34 Comments
2024/03/29
09:42 UTC

0

[Request] Wondered if anyone’s got an idea on how you’d quantify what the chances are

2 Comments
2024/03/29
08:35 UTC

121

[Request] Is it possible

So i want to know if it is possible that a strong enough wind could knock me and this motorcycle sideway? And if so how strong is it?

Some number: this vehicle is 93kg (205lb) and i am 80kg (176lb). I am travelling at a speed of 60km/h (or 40Mph).

10 Comments
2024/03/29
08:07 UTC

671

[RDTM] How long he'd have to stay in a room to get a "few million bucks"

73 Comments
2024/03/29
06:16 UTC

6

[Request] when would generation A have been?

Using the naming convention that started with gen x and using gen y for millennials we can start assigning letters to all the generations. Using this framework when would the original generation a have been?

If it helps the dates associated with each generation are 2010-2024 for gen alpha, 1996-2010 for gen z, 1981-1996 for millennials (gen y), 1964-1980 for gen x, 1945-64 for boomers (W), 1928-1944 silent (gen V), 1901-1927 greatest (gen U), 1883-1900 Lost (gen T), etc I hope that’s enough to extrapolate

9 Comments
2024/03/29
04:15 UTC

1

[REQUEST] How would I determine which character is better to use for crafting here?

How would I determine which character is better when used for crafting in this game I play? 1 instance of crafting consumes 3 blue tier books and you receive 1 purple tier book at the end. For each instance of crafting, Xingqiu has a 25% chance to give 1 blue book back (only 2 of the 3 blue books are consumed by the crafting and you get 1 purple book at the end), while Layla has a 10% chance to give 1 extra purple book (3 blue books are consumed and you get 2 purple books at the end). How do I determine which will give me the best chance at maximizing my profit in purple tier books overall, particularly when doing many instances of crafting at a time?

https://preview.redd.it/77e8ult4q6rc1.png?width=1920&format=png&auto=webp&s=93daf6bdab85740904252034e99b4e89468b1cd9

3 Comments
2024/03/29
02:50 UTC

0

[REQUEST] Help us guess how many eggs are in the jar

5.6 L jar 19 mini egg circumference 9 mini egg average height Cadbury mini eggs. Please help 🙏🙏

4 Comments
2024/03/29
02:17 UTC

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