Explanation.....

2n seats. Let's put a separator between any two seats (just to be easy to imagine).

So there are 2n-1 separators. For each separator, the situation can be M sep M, or M sep F, or F sep M, or F sep F.

So the probability of one male one female is 1/2.

The expected value is (2n-1)*(1/2)

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• 回复：Explanation..... -wushuihe- ♂ (68 bytes) () 11/11/2010 postreply 17:50:48