Answer:
There are 1,037,158,320 ways to choose a committee of 18 among 33 students.
There are 4,939,200 ways to choose 5 freshmen from 7, 6 sophomores from 8, 4 juniors from 8, and 3 seniors from 10.
Explanation:
33!/18!15! = 1,037,158,320
7!/5!2! * 8!/6!2! * 8!/4!4! * 10!/7!3!
= 7*3 * 7*4 * 7*5*2 * 10*4*3 = 4,939,200