A drawer contains 10 black socks and 10 white socks mixed completely at random. What is the minimum number of socks you must pull out in the dark to guarantee you have at least one matching pair?
3
Using the Pigeonhole Principle: if you pull 3 socks, there are only 2 possible colors (black and white). By drawing 3 socks, at least two of them must be the same color, guaranteeing a matching pair.
About this riddle
Math riddles hide a calculation inside a short story. Pull out the numbers, work out what is being asked, and watch for a trick such as a unit change.
Difficulty: Medium. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
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