I met two natives on an island - Benny and Lenny. They are either a knight, a liar or a knave. Knights always tell the truth, liars always lie and knaves alternate between truth and lie. They tell me this:

Benny : We are both of the same type.
Lenny : I am a knave.
Benny : Lenny is a liar.

A knight then tells me what Lenny is. From this I was able to work out what they were.

What are Benny and Lenny?

From the statements we know that either

• Lenny is a knave implying Benny could be a knave or a liar,
• Lenny is a liar implying Benny is a knave

Since the knight gaveLenny's type and there was just one solution for Benny then we know that Lenny must be a liar and Benny a knave.

 

Posted by Andre on 2010-06-02 18:48:21