TT-GWD-2-31

friend_friends

Q31:

There are 8 magazines lying on a table; 4 are fashion magazines and the other 4 are sports magazines.  If 3 magazines are to be selected at random from the 8 magazines, what is the probability that at least one of the fashion magazines will be selected?

 

 

A.     1/2

B.     2/3

C.     32/35

D.     11/12

E.      13/14

答案是E, 请问解题思路？

kenisjacque

 只要算出全部不选fashion magazines 的概率,即全部选 sports magazines.的概率为C(4,3)/C(8,3)=1/14

用1减去一个都不选的概率,即1-1/14=13/14

friend_friends

如果把at least 换成 only 呢……？