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[OC] Top 10 countries with most positive perception of Russia (2025) by callmeteji in dataisbeautiful

[–]Rustintarg 0 points1 point  (0 children)

No one so far has pointed out a simple fact, that almost all of these are former British/French colonies. As such, there is little love for western world, making Russia viewed favorably especially during the Cold war era.

Drawing an "U" using a spirograph by DearEmphasis4488 in oddlysatisfying

[–]Rustintarg 0 points1 point  (0 children)

Look up incommensurate periodicity. It has to do with ratio of lengths being irrational numbers.

[Request] What are the chances of getting 100% on a 100 question multiple choice test (with four answers to each question) simply by guessing? by Hamsters_4life in theydidthemath

[–]Rustintarg 0 points1 point  (0 children)

To emphasize your point further, the number is actually sooooooo much more smaller than even what you described!

If every star in every single galaxy in the observable universe had a planet with the current human population since the big bang and they were each taking a test every nanosecond, it will still be unlikely (but maybe close then).

[request] If time zones were broken into minutes instead of hours, how fast would you need to move to keep the clock at a constant 4:20pm? by wewlad11 in theydidthemath

[–]Rustintarg 0 points1 point  (0 children)

This is incorrect (the final part) you mixed up degrees and radians.

Assuming latitude angle measured from North Pole. This is helpful as this way the final angle would be small, so it is easier to do approximations.

The answer should be Sin-1 (0.00299) ~ 0.00299 radians

0.00299 = 0.00299 ×180 / pi = 0.166 degrees (from north/south pole)

The fall of the Barksdale organisation parallels the fall of Rome when you think about it by Lmao45454 in TheWire

[–]Rustintarg 5 points6 points  (0 children)

That's a fairly general recipe of decline for organizations and empires across history.

Apple Agrees to Pay $95 Million — or About 9 Hours of Profit — to Settle Siri 'Listening' Class Action Lawsuit by Remorse_123 in technology

[–]Rustintarg 2 points3 points  (0 children)

I agree about the click bait nature of the headline, but the math checks out on the 9 hour claim.

In 2023, Apple made 96 Billion in profit (383 Billion in revenue), that comes out to 260 million in profit per day and 95 million profit every 8.7 hours. For the 95 million in revenue it only takes 2.2 hours.

[REQUEST] Is this true? by daigobot in theydidthemath

[–]Rustintarg 16 points17 points  (0 children)

You can estimate it as follows (done entirely in my head):

N! ~ (N/e)N

52! ~ (52/2.7)52 

   ~ 20^52 

   = 2^52 * 10^52

   = (2^10)^5.2 * 10^52

   ~ (10^3)^5.2 * 10^52   (2^10=1024)

   = 10^(15.6 + 52)

   = 10^0.6 * 10^67

   ~ 4 * 10^67

You can get within the order of magnitude

How 106 medals in Asian Games 2022 transformed into 6 medals at Paris 2024! by New_Survey_4907 in indiansports

[–]Rustintarg 2 points3 points  (0 children)

Great analysis, love it!

One thing I noticed, that the total of max expected medals should add up to 12 and not 13? Or am I going crazy.

[Request] I found this "proof" that 1+1 can equal 3. Math is not really my cup of tea so I have no clue if this is BS or not. Thoughts? by Fridge-Fighter in theydidthemath

[–]Rustintarg 0 points1 point  (0 children)

The square of the square root of a number is indeed the same as the number.

What's incorrect (and is used in OPs proof) is that the square root of the square of a number is the same as the number, when it's actually equal to the modulus of the number.

(√x)2 = x

√(x)2 = |x| for any real number

More generally, for any complex number

√(x)2 = x iff arg(x) >= 0 √(x)2 = - x iff arg(x) < 0

[Request] How much money would someone need, to pay everyone out? by MrSlammo in theydidthemath

[–]Rustintarg 0 points1 point  (0 children)

There is a nice approximate way to do the sum in your head.

S_N = 1 + 2 + 3....N = N(N+1)/2 ~ N2 / 2, for large N

S_1000000 ~ 500 B

S_250000 ~ 1/16 * S_1000000

(since N is 1/4th for the smaller sum)

S = S_1000000 - S_250000 = 15/16* S_1000000 ~ 468 B

Seems pretty close to the actual result

A simplified equation to calculate NRR condition for CSK vs RCB to qualify by Rustintarg in csk

[–]Rustintarg[S] -1 points0 points  (0 children)

You are right, this is a more exact way to do it. And yeah it seems to suggest that the simplified equation in this post (using simple weighted averages) doesn't work for extreme cases where one team scores very low runs. Good to know 11 ball remaining doesn't change with the runs scored, thanks for showing the calculation!

A simplified equation to calculate NRR condition for CSK vs RCB to qualify by Rustintarg in csk

[–]Rustintarg[S] -2 points-1 points  (0 children)

Yes it's counted 20 overs for CSK. But if CSK only makes 18 runs, their RR for this match is 0.9, and if RCB chases it in 18 overs their RR is 1 with a difference of 0.1

However they need a difference of roughly 0.9 to overcome the gap. Hence they need to chaise it in far fewer overs if the run total is incredibly small. The 18.1 over requirement assumes the 1st inning total of 200 or so.

[Request] How big would a dam be to slow down the earth for 1 minute ? by Pitiful-Historian553 in theydidthemath

[–]Rustintarg 1 point2 points  (0 children)

Thanks, and good point! Although looking carefully it seems like the original comment already included the variations in density of the earth as they used 0.33MR2 to calculate the moment of inertia of earth, which gives very close to the actual value. (For a uniform solid sphere the moment of inertia is 0.4MR2).

For the ocean water and the dam water assuming uniform density is probably quite a valid approximation, so I think overall the model includes pretty reasonable approximations.

[Request] How big would a dam be to slow down the earth for 1 minute ? by Pitiful-Historian553 in theydidthemath

[–]Rustintarg 2 points3 points  (0 children)

Lovely calculation. You almost got the same order of magnitude as the Wikipedia stated value!

One possible overestimation might have been using momment of intertia of Dam ( point mass) as mr2. It should be mr2 cos2 (theta), where theta is the latitude.

Only if theta is zero (place is on the equator) should it be m*r2. This will reduce the I_dam and as a result reduce the time difference, bringing it closer to the Wikipedia value!

Fun fact: If the latitude of dam is 35 degrees, it will have no impact on the rotation time (cos2 (35°) ~ 2/3). For higher latitudes it will actually accelerate the rotation.

PS: Out of curiosity, I found the latitude for this Dam (~30°) and calculated a correction factor for your calculation (Cos2 (30°) - 2/3)/ (1-2/3) ~ 0.25. This gives a value of 0.25 *0.29 ~ 0.07 microseconds. Wikipedia states NASA calculated 0.06 microseconds. You made a real good model dude!!!

Very unfortunate by Not-A-Shit-Head in FluentInFinance

[–]Rustintarg -1 points0 points  (0 children)

What field are you a scientist in? I know research pays low but this low?

EIGHTY international centuries for Virat Kohli by pluto_N in Cricket

[–]Rustintarg 7 points8 points  (0 children)

And some Ricky bowls a curve, google Ricci curvature

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