如此写下2X2表,你会发现什么?
如果记下:考的是5题,没考的是N题,猜考10题,猜没考的是N-5题
所有跟帖:
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2X2
-壮士-
♂
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10/25/2012 postreply
14:30:54
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when N is very big, N/(N+5) is close to 1, then your is correct
-linda2-
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(416 bytes)
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10/25/2012 postreply
14:52:48