Three boxes are labeled: Box 1 ('The $100 is in this box'), Box 2 ('The $100 is not in this box'), and Box 3 ('The $100 is not in Box 1'). If at most one of the three statements is true, which box contains the $100?
Box 2.
If $100 is in Box 1, statements 1 and 2 are both true (2 truths). If $100 is in Box 3, statements 2 and 3 are both true (2 truths). If $100 is in Box 2, statement 1 is false, statement 2 is false, and statement 3 is true (exactly 1 truth). Thus, the money is in Box 2.
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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