In a drawer, there are 10 black socks and 10 white socks mixed randomly. The room is completely dark. What is the minimum number of socks you must pull out to guarantee you have at least one matching pair of any color?
3
By the pigeonhole principle, if you pull 3 socks, you can have either 3 of one color (which guarantees a pair) or 2 of one color and 1 of the other (which also guarantees a 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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