A drawer contains 10 black socks, 10 white socks, and 10 blue socks all mixed together in total darkness. What is the minimum number of socks you must pull out to guarantee you have at least one matching pair of any color?
4 socks
By the Pigeonhole Principle, with three possible colors (categories) and pulling 4 socks, you are guaranteed to have at least two socks of the same color, forming a matching pair.
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: Easy. More like this: Logic riddles with answers or try Einstein's Logic Grid for a different kind of puzzle.
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