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Comments 6

Multiples of 8 plus 1

Fair enough - I'm an engineer...I know just enough math to be dangerously wrong sometimes. You might enjoy this one if you haven't seen it already.

Multiples of 8 plus 1

Ah too bad - you publish any of these, by chance?

Carpeting a Donut

The cool thing in the 2nd solution is that it uses intuition about the question

the answer is the same regardless of r1's value, and will remain the same even as it diminishes to 0

It's an interesting way to look at problems in general...of course you can't always assume that what you think you see or don't see in the question is intentional.

Multiples of 8 plus 1

Very interesting proof. Are there any other patterns like this that exist among square (or nth powers in general)?

3 Coins

Good call applying Bayes' Theorem that way. My first thought was to use the HH information just to eliminate the all-tails coin. I think your logic is valid.

12 Identical Balls

I've heard the variant of this where there's one ball that's heavier, but that's muuuch easier.


Submitted Puzzles 2

8 Unfair Coin
Say you have an unfair coin: a coin whose probability of flipping heads and flipping tails is unknown but nonzero. Can you design a game where you and your opponent have an equal chance of winning?
9 13 3 Coins
Not sure what the answer is, ideas welcome! You have 3 coins, one always comes up heads, the second always comes up tails, and the third is a fair coin. You select a coin at random. After selecting ...