A room contains 80 sophomores of which 39 are males and 41 are females. There are also 69 juniors of which 36 are males and 33 are females. You pick 3 students at random. What is the probability that all 3 are males?
total males: 39+36=75
total students: 80+69=149
you are basically just selecting without replacement, so
P(3 males) = 75/149 * 74/148 * 73/147