A thief steals a pocket watch and hides it inside one of three identical wooden boxes labeled A, B, and C. On Box A it says: 'The watch is in this box.' On Box B it says: 'The watch is not in this box.' On Box C it says: 'The watch is not in Box A.' Exactly one of these statements is true. Which box contains the watch?
Box B
If the watch is in A, both A and C are true (contradicting the rule of only one true statement). If the watch is in C, statements B and C are both true (again a contradiction). If the watch is in B, only statement C is true ('The watch is not in Box A' is true, while A and B are false).
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: Hard. More like this: Logic riddles with answers or try Einstein's Logic Grid for a different kind of puzzle.
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