Probability Question: Among 500 freshmen pursuing a business degree at a university

Among 500 freshmen pursuing a business degree at a university, 314 are enrolled in an economics course, 248 are enrolled in a mathematics course, and 147 are enrolled in both an economics and a mathematics course. What is the probability that a freshman selected at random from this group is enrolled in each of the following? (Enter your answers to three decimal places.)

(a) an economics and/or a mathematics course

(b) exactly one of these two courses

(c) neither an economics course nor a mathematics course

314+248-147 = total enrolled in one or both = 562-147 = 415
415-147 = exactly one course = 268

500-415 = number enrolled in neither = 85

(a) an economics and/or a mathematics course
p=415/500 = 0.830

(b) exactly one of these two courses
p = 268/500 = 0.536

(c) neither an economics course nor a mathematics course
p=85/500 = 0.170

check my arithmetic .. did it in my head with not enuf coffee