回复:数学题求救,先谢了

回答: 数学题求救,先谢了琼岛春荫2012-04-12 07:10:10

1. (10C1)x(9C3)x7!/4!x9/10=158760

2. (10C2)x(8C3)x7!/2!/2!x9/10=2857680

 

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these two answers are right -calligraphy- 给 calligraphy 发送悄悄话 (0 bytes) () 04/13/2012 postreply 17:21:26

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