A detective establishes two facts: 1. If the butler lies, then the maid is innocent. 2. If the maid is innocent, then the chef is guilty. The chef is later proven innocent. Is the butler telling the truth or lying?
The butler is telling the truth
Since the chef is innocent, by contrapositive of rule 2, the maid must be guilty. By contrapositive of rule 1, if the maid is guilty, the butler is not lying (telling the truth).
About this riddle
Logic riddles give you a few facts and ask what must be true. List what you know, cross out what cannot be, and see what is left.
Difficulty: Medium. More like this: Logic riddles with answers or try Einstein's Logic Grid for a different kind of puzzle.
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