An adventurer found a locked treasure chest in a dungeon. He tracked down three brothers (each either a Liar or a Knight) one of whom has the key to open the chest.

Each made a statement:

A: I have the key to the chest.

B: I don't have the key to the chest.

C: B Doesn't have the key.

The adventurer knows that at least one of the three is a Liar, and at least one - a Knight. Who has the key?

C has the key.

If A had the key, all three statements would be true, so they would all be knights.

If B had the key, all three statements would be false.

But since C has the key, A is a Liar, and B and C are Knights, which meets the requirement of at least one Liar and one Knight.

Posted by Ender on 2002-05-17 07:13:04