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.
The trouble with saying that the truth tellers are mistaken is, allowing for this would not allow for a solution to ANY logic problem of this sort. Hey, maybe Barry stole it while he was drunk and just doesn't remember. Maybe Allen doesn't realize that Fred is reading lips and believes that he can hear. If we assume that this problem follows the standard parameters, the only solution, given the data, is that none of the six is the thief. I think this problem is just badly worded. If the wallet was lost instead of stolen, the final question should be, "what happened to the wallet?" If a person other than the six stole it, that person should have been mentioned.