请教OG11 -180

guozili

in a nationwide poll,N people were interviewed.if 1/4 of them answered"yes" to question1,and
of those,1/3 answered "yes" to question2,which of the following expressions represents the
number of people interviewed who did not answer "yes" to both question?

A N/7
B 6N/7
C 5N/12
D 7N/12
E 11N/12

请教各位NN，

1，不太理解and of those 1/3 answered"yes " to question2，其中的those指的是全体N？还是N/4

2，我得思路是这样

A: yes yes

B: yes NO

C  NO yes

D  NO NO

A+B=N/4

B=N/12

凭A跟B的已知条件，就能够求出D吗？实在不理解，请NN解答，多谢了！

[此贴子已经被作者于2007-8-9 3:20:02编辑过]

sammy生米

of those的those指N/4

第1个问题答yes有N/4人

2个问题都答yes的有N/4*(1/3)=N/12人，所有不同时答yes的有1-N/12人，即11N/12人

E吧

guozili

多谢！唉，我对题目理解的太歪了！多谢！

geoffrey29

who did not answer "yes" to both question，这个是说“没有都选yes的人”

请问怎么表达“都没有选yes的人”