In a secret society, every member is either a Truth-Teller who always tells the truth, or a Liar who always lies. You meet two members, Arthur and Betty. Arthur says, 'We are both Liars.' What are Arthur and Betty?
Arthur is a Liar, and Betty is a Truth-Teller.
If Arthur were a Truth-Teller, his statement 'We are both Liars' would be a lie, which is a contradiction. Therefore, Arthur must be a Liar. Since his statement is false, it is not true that they are both liars, meaning Betty must be a Truth-Teller.
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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