gwd6-22

detectiveyan

Q22:

A certain company assigns employees to offices in such a way that some of the offices can be empty and more than one employee can be assigned to an office. In how many ways can the company assign 3 employees to 2 different offices?

A. 5

B. 6

C. 7

D. 8

E. 9

请教思路

sportman

把3个人，往2个办公室里扔。

每个人都有两种选择。2^3=8.

detectiveyan

谢谢及时的回复，我没理解下面这句话：

in such a way that some of the offices can be empty and more than one employee can be assigned to an office

这是不是等于说可以随便分没有限制？

kenlily

对.那句话是说:

用这样一个方法,可以有办公室是空的,也可以多个人都塞到一个办公室里.

observer

1 有一个办公室是空的（任意）

则有2种情况

2 两个办公室都不为空，则必有一个是1个人的（任意）

c(3,1)*c(2,2)*2=6

so 2+6=8