Best riddles


Prisoner sentenced to death

You are a prisoner sentenced to death. The Emperor offers you a chance to live by playing a simple game. He gives you 50 black marbles, 50 white marbles and 2 empty bowls. He then says, "Divide these 100 marbles into these 2 bowls. You can divide them any way you like as long as you use all the marbles. Then I will blindfold you and mix the bowls around. You then can choose one bowl and remove ONE marble. If the marble is WHITE you will live, but if the marble is BLACK... you will die." How do you divide the marbles up so that you have the greatest probability of choosing a WHITE marble? HINT: The answer does not guarantee 100% you will chose a white marble, but you have a much better chance.
Place 1 white marble in the bowl, and place the rest of the marbles in the other bowl (49 whites, and 50 blacks). This way you begin a 50/50 chance of choosing the bowl with just one white marble, therefore life! BUT even if you choose the other bowl, you still have almost a 50/50 chance at picking one of the 49 white marbles.
90.47 %
44 votes


Magic number

Ramanujan discovered 1729 as a magic number. Why 1729 is a magic number ?
It can be expressed as the sum of the cubes of two different sets of numbers. 10^3 + 9^3 = 1729 and 12^3 + 1^3 = 1729
90.47 %
44 votes


Time of day

What time of day, when written in a capital letters, is the same forwards, backwards and upside down?
90.29 %
25 votes


The ladder

A boy fell off a 30 meter ladder but did not get hurt. Why not?
He fell off the bottom step.
90.26 %
43 votes


Tiling Without Corners

You can easily "tile" an 8x8 chessboard with 32 2x1 tiles, meaning that you can place these 32 tiles on the board and cover every square. But if you take away two opposite corners from the chessboard, it becomes impossible to tile this new 62-square board. Can you explain why tiling this board isn't possible?
Color in the chessboard, alternating with red and blue tiles. Then color all of your tiles half red and half blue. Whenever you place a tile down, you can always make it so that the red part of the tile is on a red square and the blue part of the tile is on the blue square. Since you'll need to place 31 tiles on the board (to cover the 62 squares), you would have to be able to cover 31 red squares and 31 blue squares. But when you took away the two corners, you can see that you are taking away two red spaces, leaving 30 red squares and 32 blue squares. There is no way to cover 30 red squares and 32 blue squares with the 31 tiles, since these tiles can only cover 31 red squares and 31 blue squares, and thus, tiling this board is not possible.
90.26 %
43 votes


6 afraid of 7

Why is 6 afraid of 7?
Because seven was hungry and 'seven ate nine' (7, 8, 9).
90.26 %
43 votes


Five Men Like Pete

Pete is a worker on a large ship with hundreds of other men. He is constantly making mistakes, tying ropes the wrong way, steering the ship the wrong way, and making other blunders. One time he accidentally caused the ship to get stuck in a shallow shore, causing thousands of dollars in damage. However, when Steve, the captain of the ship, is asked about Pete, Steve says "I wish we had five men like Pete on this ship." Why would he say this?
90.04 %
42 votes