Critical Thinking Puzzles

You have the misfortune to own an unreliable clock. This one loses exactly 20 minutes every hour. It is now showing 4:00am and you know tha...

A man tosses three coins in the air. When they land, he finds that two of the coins have heads up and one has tails up. What is the probabi...

You have 32 numbers. What is the least number of comparison needed to find the 2nd smallest out of them?

In chess, queens can move horizontally, vertically, or diagonally, as far as they like, as shown in the picture. We say that a queen can ...

Which clock works better? The one that loses a minute a day or the one that doesn't work at all?

X and Y are two different integers, greater than 1, with sum less than or equal to 100. S and P are two mathematicians; S knows the sum X+Y...