1-P(30,7)/30^7=53.1%
53.1%
所有跟帖:
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P(30,6)*C(7,2)/30^7=0.410511111,I use 5 people carelessly.
-jinjing-
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04/23/2010 postreply
13:22:21
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agree~~~
-cheerleaders-
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04/23/2010 postreply
17:13:05