/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.


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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

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  2. Request
  3. Non-Request
  4. Self
  5. RDTM
  6. Off-Site

/r/theydidthemath

1,595,688 Subscribers

1

[Request] How Heavy Would the Stingray Have Been?

Hello! Sorry if this post isn't formatted correctly; it's my first time posting here!

I wanted to ask: Any River Monsters fans here? I wanted to see if we could calculate how large the stingray in this video (https://youtu.be/bI0NSCF8H9E) could have been to bend the rod at such a hard curve - AKA, how much weight could have been behind it. From what I could find, Jeremy used braided nylon filament line and a carbon fiberglass rod designed for ocean fishing, and he apparently called the gear "marlin gear", if that helps anything, and he's made comments that he's around 175 pounds himself.

To compare, the stingray that Jeremy did succeed in catching weighed around 400 pounds, and I think he estimated that the lost stingray was around 700 pounds.

1 Comment
2024/11/18
23:24 UTC

9

[Request]Like the other post, I'm really curious how to calculate THIS % of perfect circle

2 Comments
2024/11/18
21:54 UTC

4

[request] how small would earth have to be for the average able-bodied human to see the bottom of challenger deep?

image credit to kmusser, no changes made. https://commons.m.wikimedia.org/wiki/File:Marianatrenchmap.png

11 Comments
2024/11/18
21:50 UTC

4

[Request] How much radium to cover the car

LTT just made a video wrapping a Porsche (Taycan 4S) to make it glow. If you instead covered this car in old paint from the 1950s made of tritium or radium so that it glows all the time how much of either material would be needed and what would it cost?

2 Comments
2024/11/18
21:38 UTC

3

[Request] Can you turn a rooster to a hen this way?

Let's assume they're 90kg

9 Comments
2024/11/18
21:11 UTC

504

[Request]I have gotten into an argument over this. The kid is wrong right? Because it isn't asking what the commutative answer is it is asking how you would write 3x4 into an addition equation correct? So you have 4+4+4=12 not 3+3+3+3=12 since that would be 4x3 RIGHT!? This is stupid I am sorry.

415 Comments
2024/11/18
19:34 UTC

3

[Request] What are the odds that me and my friend did 10 coin flips each and got the same result on each flip

5 Comments
2024/11/18
19:11 UTC

0

[Request] How strong would the bite force of a titan from "Attack on Titan" be?

considering the fact that each titan is about 15 meters tall and low estimates would be 2-3 and high estimates would be 4-6 times stronger than a human of equivalent size (source:Eren carrying that rock), how strong would the bite force of one of these dudes be??

3 Comments
2024/11/18
17:45 UTC

0

[Request] Same birthday

For starter i don't know if this is calculable, if it's not i apology.

In my office we are 8 people and there is 4 people with following birthday 4-5-6-7 december (not the same year). Can the odds be calculated ?

(i know about the birthday problem, with a group of 23 people there is a 50% chance of 2 people having the same birthday, maybe there is something like that)

3 Comments
2024/11/18
17:03 UTC

1

[Request] How much would a Year 1 and 2 teacher in the UK earn, if they got paid for all the work they did outside of their usual school working hours?

1 Comment
2024/11/18
16:41 UTC

8

[request] How long for this box to fully change color?

This may be a long shot but I figured this community was the place to go. On October 18 the website for the band bon iver updated their landing page with two identically colored squares on either side of the page - https://boniver.org. As you can now see the square on the left is gradually changing to a lighter shade. Working theory is that it will become a hue on salmon that is heavily featured in promotion of their EP (see attached photo). Based on the start date of 10/18 and the current hue of the left square can anyone calculate a potential date that it may fully reach the salmon color? Like I said it’s a long shot. Thanks so much for any help!

7 Comments
2024/11/18
16:24 UTC

120

[Request] how to calculate the % perfect circle a curve is

Came across this website that measures the % of how "perfect" the circle is... Wondering what metric can you use for that? And in general, how can you measure how "circular" any curve is?

Mor info- there is only one dot that represents the center of the circle. The radius doesn't seem to matter in the calculation from my multiple attempts. However, it does say too close when you try to draw a circle with a very small radius.

42 Comments
2024/11/18
15:06 UTC

0

[REQUEST] How much could the atmosphere be oxygenated before humans would start to have issues?

Title. Also, when adding oxygen, assume that oxygen is being added to our pre-existing atmosphere, not replacing current chemicals (Eg. Pressures will go up as well).

2 Comments
2024/11/18
14:56 UTC

0

[Request] Is there a safe way to shoot someone from a cannon?

Asking for a friend.

6 Comments
2024/11/18
14:08 UTC

1

[Request] same dimensions yield different results. How?

So I have two interconnected tanks, a big and a smaller one as shown in the attached screenshot. The goal is to find the total capacity of both tanks in cubic metres.

I made the calculation in two different ways and the results were different. I cannot explain why... Any thoughts?

Calculations:

  1. Calculate the cubic meters of each tanks and sum them together at the end (in the screenshot green arrow/rectangular). This returns 0.861m³

  2. Sum up the width, length and heights of both tanks and then multiply their totals to find the capacity (in the screenshot red arrow/rectangular). This returns 3.169m³.

I know that the first calculation is is the correct one as I know that the capacity of both tanks is approximately 1m³.

4 Comments
2024/11/18
13:31 UTC

276

[request] what are the odds of this happening?

27 Comments
2024/11/18
13:16 UTC

0

[request] how many light years have they run? (The distance travelled)

7 Comments
2024/11/18
12:52 UTC

1

[REQUEST] at what cycle does the correct DNA becomes prevalent in a PCR?

So, the original DNA (lets call it "22" because both single strands have extra info we dont want) splits into two "21" (one original with 2 residues, 1 recreated, with 1 residue). Like so, 21 becomes 21 + 11; 11 becomes 11 + 10; 10 becomes 10 + 00 (the desired DNA, assuming im understanding correctly)

Now, I get that the original dna (22) dissapears, and that "21" becomes a constant at 2, but does the correct (00) sequence ever becomes predominant or will it always be shadowed by partially correct ones? And if so, at what cycle?

Thanks in advance!

2 Comments
2024/11/18
12:18 UTC

26

[Request] Is this accurate? How many squaremeters of the US are parkingspaces? What percentage of the US is parking space?

12 Comments
2024/11/18
11:35 UTC

0

[REQUEST] Hey could someone pls give me a visual of what 250m2 looks like pls and thx

Here's a cookie for Ur hard work 🍪

13 Comments
2024/11/18
11:24 UTC

2

[RDTM] - Nuclear Nut

0 Comments
2024/11/18
10:24 UTC

1,092

[Request] How strong would Peter have to be to hold himself to the chair if gravity vanished?

51 Comments
2024/11/18
09:51 UTC

42

[Request] If this was accurate, how many square miles would Ireland be?

4 Comments
2024/11/18
09:46 UTC

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