Tagged Questions

Puzzles, curiosities, brain teasers and other mathematics done "just for fun".

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pick three drawing

Our veterans club has a daily pick 3. We currently have one cage with 30 balls numbered 0 thru 9. The first number is drawn and returned to the cage and the next two the same way. I believe this gives ...
33 views

Toroidal Split Complete Graphs

The paper On the Planar Split Thickness of Graphs shows how non-planar graphs can be split to make planar graphs. For example, they offer a split $K_{6,10}$. I would instead like to make split ...
101 views

(Green/blue)-eye logic puzzle. Statement validation

There is a logic puzzle aiming on freeing same-color-eyed people from an island. The thing is that they must be certain of their own eye color so that they can leave. For that reason an external party ...
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Filling a grid square with 0,1,2 [duplicate]

Each of the 25 cells in a five-by-five grid square is filled with a 0, 1, or 2 in such a way that the numbers written in neighboring cells differ from the number in that cell by 1. Two cells are ...
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Can this be proved using single variable calculus or there's something wrong with this problem [closed]

If $y^{1/m} + y^{-1/m} = 2x$ then prove that $(x^2 - 1)y_{n+2} + (2n + 1)x y_{n+1} + (n^2 - m^2)y_n = 0$? Where $y_n$ denotes the $n^th$ derivative of $y$. This is a question of successive ...
42 views

Absolute difference and probability [closed]

Fifty tickets numbered with consecutive integers are in a jar. Two are drawn at random and without replacement. What is the probability that the absolute difference between the two numbers is 10 or ...
67 views

The growth rate of $(\ln(x))^n$ is a lot slower than I expected

Obviously, the growth rate of $(\ln(x))^a$ is less than the growth rate of $(\ln(x))^b$ as long as $a>b$. Also, the growth rate of $(\ln(x))^n$ is apparently always less than the growth rate of $x$...
37 views

heart rate problem [closed]

The average heart rate of a shrew is 800 beats per minute, while an elephant has a heart rate of 25 beats per minute. If 1 billion heartbeats is a natural life span for each animal, on average, how ...
70 views

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Does this graph partitioning algorithm achieve anything interesting?

I was musing over graph clustering and partitioning, and isolating clusters, and came up with an algorithm that I think might do some interesting things. I figured I'd run it past here to get some ...
155 views

Recreational problems in set theory?

Most areas of maths that I can think of have a number of fun, recreational problems that come under their category. Nothing deep: number theoretic stuff in olympiads, integrals, limits, products, ...
41 views

Assumption and simple calculation

I'm having an issue with what seems to be an simple question. Here it is: Two hockey teams, team A and team B played a game, Team A beat Team B by 2 goals. The crowd was pleased as there were 8 ...