A small boat is floating in a swimming pool. The boat contains a very small (very very very small) but very heavy rock. If the rock is tossed out of the boat into the pool, what happens to the water level in the pool? It is related to Physics, but also common sense. A floating …

## Brainteaser #4

I have a 20*20 chessboard and a very large box of identical cubes. Each square on the chessboard is the same size as the face of any cube. I am going to arrange piles of cubes on the chessboard in a special pattern. I align one edge of the board so it is running north-south. …

## Brainteaser #3

## Brainteasers #2

are the nine integers from one to nine (not necessarily in order). They satisfy the following constraints: What values are taken by each of A to I? Answer below: Since and sum to 40, must be 5. If E is 5, subtracting equation 1 with equation 2, A – 5 – F = 0; subtracting …

## Brainteasers #1

Flip 98 fair coins and 1 HH coin and 1 TT coin. Given that you see an H, what is the probability that it was the HH coin? Explain in layman’s terms. Fair coins: Head (H) and Tail(T)HH coin: Both sides are headTT coin; Both sides are tail Answer below: There are 100 heads in …