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Here is a cooler problem, imo: show that the expected value of the # of people who get their hat back is 1, independent of n.

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How is this cooler? This is way easier to solve than the original problem, just use <font color="white"> indicator functions </font> &lt;---- answer in white.

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Cooler in that it admits several elegant and simple solutions. To me, easier problems are cooler.

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Can't disagree with that =).

That post also jarred my memory and reminded me of an amazingly simple solution to the 1st problem using exponential generating functions. Thanks [img]/images/graemlins/smile.gif[/img]