At the library 200 people were surveyed about magazines they read. 75 read US News, 45 read Rolling Stone, 120 read Time.
15 read all three magazines.
20 read US News and Rolling Stone;
35 read Time and Rolling Stone;
40 read Time and US News;
a) Find how many people read at least 1 magazine?
b) Find how many do not read any of the 3 magazines?
c) Find how many only read Time and not the other two magazines?