[求助]TT5-3

huangxiaoyan

Q3:

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D

喝咖啡的狼

法 1 

全女+全男+1男2女+1女2男= 2 X C53 + 2 X (5XC42)

法 2

所有可能 - 有COUPLE 可能 = C10 3 - 5 X 8

huangxiaoyan

多谢