This question is based on the following circle graph. the graph represents the results of a survey in which 400 people were asked to identify the tv channel on which they preferred to watch the evening news.

2. how many more people preferred wwcn than wanr? a. 164 b. 76 c. 236 d. 68

First; isn't that called a pi chart? 
Second; here' your
41% of 400 is the same as 41x4=164
22% of 400 is the same as 22x4=88
164-88=76 so the answer is B

Hope this helps :)

Post Script: I wasn't trying to be rude with the first thing if that's how it comes across, I was just wondering cause I live in England and we call them pi charts.