You meet two islanders, X and Y. One always tells the truth and one always lies. Person X says: 'At least one of us is a liar.' What are Person X and Person Y?
Person X is a truth-teller and Person Y is a liar
If X were a liar, X's statement would be false, implying neither is a liar, which contradicts X being a liar. Thus, X must be a truth-teller. Since X's statement is true ('at least one is a liar') and X tells the truth, Y must be the liar.
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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