An instructor who taught two sections of engineering statistics last term, the first with 20 students and the second with 30, decided to assign a term project. After all projects had been turned in, the instructor randomly ordered them before grading. Consider the first 15 graded projects.
(a) What is the probability that exactly 10 of these are from the second section?
(b) What is the probability that at least 10 of these are from the second section?