请教另一题

paopao

Q24:

Factor Percent of Respondents

User-friendly 56%

Fast response time 48%

Bargain prices 42%

The table gives three factors to be considered when choosing an Internet service provider

and the percent of the 1,200 respondents to a survey who cited that factor as important. If

30 percent of the respondents cited both “user-friendly” and “fast response time,” what is

the maximum possible number of respondents who cited “bargain prices,” but neither

“user-friendly” nor “fast response time?”

A. 312

B. 336

C. 360

D. 384

E. 420

答案A 怎么做啊

谢谢

lettuce

你做的时候画个图图就清楚了