TT-GWD-2-31

summertao

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？

gifile

也就是求1－3本全都是sports magazines得概率

1－C(3,4)/C(3,8)=1-1/14=13/14

gifile

at least....

这种东西，就是求1减去全都选不出这种东西得概率。

summertao

 如果把at least 换成 only 呢……？