You meet six men on a road side. The problem is that your wallet is mysteriously missing and you can't figure out if these men are truth tellers or not. So you ask a few questions and here are their answers:
Allan: "Fred stole it. Fred also hears quite well."
Barry: "Calvin is a liar. I did not steal it and I know Allan did not steal it."
Calvin: "Allan and Dwayne are both knights. Eddy stole it."
Dwayne: "Allan is a liar. I did not steal it."
Eddy: "Only 4 of us are knights. I did not steal it. I know Calvin did not steal it."
Fred: "I am deaf but read lips. Barry did not steal it."
Who stole the wallet?
P.S. You are sure that all of the men either lie or tell the truth. No one does both.
I think that we managed to determine that Allan and Calvin are both liars while every one else are knights, but who stole the wallet.
So lets examine the statements pretaining to who stole the wallet. Is safe to assume that since knights always tell the truth, they will alway know the truth before speaking but this is not true with a liar.
The knights always say "I know ..." while liars just say "... stole it" which implies that they might know the truth or not and just pointing fingers. When Calvin accuses Eddy of stealling the wallet, Eddy says that he did not steal the wallet and since he is a knight we know this is true. When Allan accuses Fred, Fred is not denying it.
So I know it is far fetched but I think FRED STOLE THE WALLET.