You meet three people, A, B, and C. Each one is either a knight or a liar. A and B make these statements.
A:We are all of the same type.
B:A and C are of different types.
What are A, B, and C?
A = Liar
B = Knight
C = Knight
If [A = Knight], then [B & C = Knight]. But that would make B's statement False. Therefore, [A = Liar].
If [B = Liar], then A & C would be the same  Liars. But that would make all three Liars, thus making A's statement True. Therefore, [B = Knight].
And if [B = Knight], then C must be the opposite of A, so [C = Knight] too.

Posted by hoodat
on 20110214 13:12:12 