A drawer contains 8 socks: 4 black and 4 white. You grab socks one at a time in the dark. What is the minimum number of socks you must grab to guarantee you have a matching pair?
Enter an integer
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There are 2 colors. By the pigeonhole principle, if you grab 3 socks, at least ⌈3/2⌉=2 must be the same color. The worst case with 2 socks is one black and one white, so 2 is not enough. Therefore 3 socks guarantee a matching pair.