回複：回複：依次任取7個小於等於10的正整數，求其和為20的概率？

來源: guest007 於 2010-06-07 10:01:11 [] [舊帖] [給我悄悄話] 閱讀數 : (115 bytes)

agree- seems to be a 體力活 to me too. did not a see shortcut solution.

my estimated result is about~ 0.3%.

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