A cop arrested four suspects for the bank robbery. When he interviewed them, each made two statements. From his infrared lie-detector he knew that each man made one "true" and one "false" statement. As a result, he soon found out the culprit.

Given the following statements, can you determine who the culprit was?

‘A’ said: “I did not do it. B did.”

‘B’ said: “A did not do it. C did.”

‘C’ said: “B did not do it. I did.”

‘D’ said: “C did not do it. A did.”

I believe B did it.
Method,

If you start with any of the four people and pick one of their answers to be true and one to be false you can work out which of the other three's answers are true or false, by doing this it's possible to determine that B is lying when he says C did it, whichever combination you pick. Therefore C must be lying when he says "I did it" which leaves his other statement of "B did it" as the true statement

Posted by Michael on 2003-01-31 04:27:44