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

thanks

是选 A 吗？

0.56+0.48-0.3=0.74

(1-0.74)*1200=0.26*1200=312

我是这样做的：“user-friendly” and “fast response time,” 一共占56％＋48％－30％＝74％。两者都没选的就是1－74％＝26％。所以只选Bargain prices   的最多不能超过26％，那么就是1200*26％＝312人。