The following two facts are known about Adam, Bert, and Carl:

1) Of Adam, Bert, and Carl, there is one knight, one knave, and one liar.
2) Adam said once, "Bert said that Carl isn't a knight."

Can you ask one yes/no question to one person and figure out who is who? If not, how many questions must you ask?

(In reply to Two Questions by Liam)

Quote:
"(1) Bert says "Yes", he did say that Carl is not a knight.  If this is the case, then both Bert and Adam have the same story of events and this means that both are telling the truth."

Not true.  It could be that Bert says "Yes", but is lying.  This would mean he did NOT in fact say that Carl is not a knight.  It would also mean that Adam was lying when he said that Bert had said this.  In short, a "Yes" here does NOT mean that they are both telling the truth.

Posted by John on 2005-02-17 00:03:28