gwd-5-3

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? C¹₅C¹₄C¹₆

A.     20

B.     40

C.     50

D.     80

E.      120

the answer is D,mine is E

sorry,i still don't really understand this question..

is it means that if 5 married couples actually are 10 people.

it would be very kind if anybody could give us a better and comprehensive explanation...

thank u..

C(10,1)*C(8,1)*C(6,1)/P(3,3)

c(10 3)-5c(8 1)

thank you all......

lovetiky,it's very clear why C(10,1)C(8,1)C(6,1)comes out,however,why this product need to be divised by P(3,3).

没有顺序就要除吗？对不起，我知道接下来让你解释，肯定bother u.但是，还是不理解。