Saturday, 29 January 2011

The oddness of socks

In a moment of boredom, and prompted by a recent survey of wacky interview questions, I plotted out the probability graph of finding a matching pair of socks at random, based on the number of black ones among 25 grey ones. It turns out that you need only 3 black socks to drop the probability of a matching pair from 100% to 80%; 9 in 25 gets you to 60%. Anything over that makes very little difference up to 25, where the probability drops to a minimum as you would expect. After that it starts rising again slowly, but never reaches 100%. YOU NEVER HAVE A LESS THAN 48.9795918% CHANCE OF GETTING A MATCHING PAIR. I find that oddly comforting.

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