A silent archive holds three identical golden books on a shelf, labeled 'Truth', 'Lies', and 'Mixed'. The labels were all switched incorrectly by a mischievous librarian. You may open only one book and read a single sentence to deduce all correct labels. Which book do you open, and what must the sentence say for you to solve the puzzle?
Open the book labeled 'Mixed'. It must contain a sentence that is neither entirely true nor entirely false, or you deduce based on the label rule.
Since all labels are wrong, the book labeled 'Mixed' cannot actually be mixed; it must be either all Truth or all Lies. By opening it and reading a sentence, if it contains a false statement, the book is 'Lies', meaning the other two can be instantly sorted.
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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