Professor Z was killed by one of his four students, who was helped by another of the four. His students declared:
A: If B is guilty of something, then C must be innocent.
B: If A is innocent, then C must be guilty.
C: If B was the killer, then D must have had nothing to do with the crime.
D: I am innocent.
As everybody should know, guilty parties always lie, and innocent people always tell the truth. Who killed the professor, and who was his accomplice?
Just like the paul priest guy posted, this problem has another solution or possibly just this one because i don't even understand how the other one was reached.
Let's say A is innocent and telling the truth. That would mean that if B were lying than C would be telling the truth. A is not saying that that's how it is. He's just saying If____ , then____.
Let's say that B is innocent as well and therefore also telling the truth (still not contradicting A). Then C is guilty and both A's and B's statements allow this. Then C is lying. He says If B was the killer than D had nothing to do with it. Then what he's really saying is since B is not the killer than D was involved. Making him guilt and a liar.
He says I am innocent. Obviously he's not. It all works out.
alternate solution
