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?
(In reply to
re: full solution by M. Pianalto)
Matthew, the t-value under A's statement is correct.
Since the first part of the statement is false (A isn't
innocent), the second part can be anything, and the truth value
is true.
This is similar to my saying, "If the sky is always orange, then I can fly." (A true statement.)