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.”

Two people's statements agree - A & B' first statements and B & C's second statements.
If A's first statement is true, then B's first statement is also true, meaning B & C did not do it because of their second statements. That would also make C's first statement was true, so he did not do it because of his second statement, meaning D did it.

If A's first statement is false, then he did it, but that would mean that both of B's statements are false, so that's not possible.

So the robber is D and everybody's first statement is the true one.

Posted by Lewis on 2003-06-20 10:33:58