Puzzles

12 Coins

You have 12 coins, one of which is a fake and has a different weight than the others. Using a scale (two pans) can you determine the fraud in no more than 3 uses.

5 Pirates

There are 5 pirates who must split 100 gold pieces. They use the age-old pirate tradition that the oldest pirate offers a suggestion on how to divide the gold, if the suggestion is accepted by a simple majority it is done, otherwise (even in a tie) that pirate has to walk the plank and the remaining pirates start again. What happens?

Knights and Knaves

There are two doors, behind one is a wonderful treasure, behind the other is certain death. The doors are guarded by a knight and knave who know where each door leads. Knights always tell the truth, knaves always lie. But you don't know which guard is which. You may only ask one question, how do find which door to open.