The answer only for 7 families.n families is (n-1)/(7n-1)

来源: jinjing 于 2010-06-01 11:13:51 [] [旧帖] [给我悄悄话] 阅读数 : (24 bytes)
回答: 继续热身~~ 由 guest007 于 2010-05-27 09:05:12

If n --To 00 should 1/7.

请您先登陆，再发跟帖！