If two people are of the same type,then they are either both knights or both liars. If they are of different types,then one is a knight and one is a liar. Now, suppose Drew and Mohammad say the following.

Drew: We are of the same type.
Mohammad: We are of different types.

Now, what are each?

If Drew was a knight, Mohammed would have to be one, and thus wouldn't disagree with Drew; he thus lies, and then Mohammed must tell the truth.

Posted by Federico Kereki on 2003-10-27 13:10:18