You are on a treasure hunt, wondering where the "Truth Treasure" is buried. You have no idea where it is buried, so you go Truth Town (made up of only Liars and Knights) because it is famous for holding the treasure's secret location.

When you enter the city, you see two twins and they know each other's types, but you don't. One twin says "(Exactly) one of us is a Knight..." and the other twin says "...and (exactly) one of us is a Liar." You can only ask one question and only to one person. You only care about where the treasure is kept, and obviously a liar would give you a wrong answer, so what should you do?

they both have to be liars because one says that exaclty one of them is knights and the other says that exactly one is a liar.  if the first one is telling the truth he is a knight.  tht would have to make the second one telling the truth and that can't be because he would have to be lying.  if the second is telling the truth that would make the first the liar and that can't be because he can't be lying because there would be one knight.  they both have to be lying.  so the proper question to ask them is where is the treasure not at because they would lie and there is only one spot where the tresure is. 

Posted by christopher on 2005-11-05 12:59:11