math
posted by greg .
65 men 75 women are enfolled in calculus. There are 30 business majors, 40 biology majors, 50 computer science majors, and 20 mathematics majors. No person has a double. If a single calculus student is chosen, find the probability that that the student is not a mathematics major

since there are 20 math majors in 140 students, there is a 120/140 = 6/7 chance that a calculus student is not a math major.
The men/women info is irrelevant.