help thanks a lot!!

If a committee of 3 people is to be selected from among 5 married couples so that the committee does not include two people who are married to each other, how many such committees are possible?

A.      20

B.      40

C.      50

D.     80

E.      120

答案是什么呀

思路，先从5组选3组出来，C(5,3)

然后这三组中再分别2选1，

答案80，没错，限定性的组合问题，应该算是难题了。

倒，在PREP里遇到一样的，唯一的不同是，不是5对，是从4对里面选3个人，那也应该是一样的算法吧.

结果是32？

1,c (10,3)- 5c(8,1) =120- 40 =80  费费一题和此类似

2, C(8,3)-4C(6,1)=56- 24 =32