求解一道数学题

朋友着急向我求解一道 Beestar 8th grade GT math problem. 以前解这种小题绝对没问题。年头久了，大脑生锈，这次看了半天没看出名堂，也静不下心来，坛子里常解题的高手，请帮着看一下，指指思路。非常感谢。

Beestar Grade 8 GT Math Exercise - week 3, ex. 3, summer 2012

In a tennis tournament, n women and 2n men play, and each player plays
exactly one match with every other player. If there are no ties and
the ratio of the number of matches won by women to the number of
matches won by men is 7 to 5, what is the value of n?

 

 

所有跟帖： 

• N=3 -柯西- ♀ (138 bytes) () 07/12/2012 postreply 09:10:17

• 回复：N=3 -calligraphy- ♂ (199 bytes) () 07/12/2012 postreply 12:25:35

• google is your friend -jackyhan- ♂ (1513 bytes) () 07/12/2012 postreply 09:11:11

• 回复：求解一道数学题 -Kamioka- ♀ (339 bytes) () 07/12/2012 postreply 09:11:53

• n=3, 典型的竞赛题，很多类似奥数点书都有介绍一些公式的 -Duckegg- ♂ (0 bytes) () 07/12/2012 postreply 09:12:08

• Beestar 答案是 n=3 (唯一解）。谢谢高手指点，让我消化消化。。。 -孺将- ♂ (0 bytes) () 07/12/2012 postreply 09:20:46

• yes 答案是 n=3 (唯一解）。 -Kamioka- ♀ (638 bytes) () 07/12/2012 postreply 09:25:39

• n=3 -PaulBunyan- ♂ (0 bytes) () 07/12/2012 postreply 09:30:18

• n不等于3 -壮士- ♂ (29 bytes) () 07/12/2012 postreply 09:57:53