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?
there are only two possibilities that either and c are innocent or b and c are innocent; if b is not killer means he can assist.
but if that is not so,the other possibility b and c being innocent, their statements mean
b : if a is not innocent, then c must not be guilty (justified).
c : if b was not the killer, d must have had something to do with the crime (justified).
a : if b is 'not' guilty of something, then c is innocent. (lie inverted justified).
d : he is not innocent. (lie inverted justified).
but then who exactly killed the Professor among a and d ?
if d is not the killer...
