Deyoung International Academy has students with the following grades: 10% had an A; 75% had a B; 10% had a C; and 5% had D's. In using these grades, answer these questions about a sample of 10 students that were selected at random.
- What is the probability that 1 student had an A?
- What is the probability that 3 or fewer students had a C?
- What is the probability that exactly 4 students had B's?
- What is the probability that at least 2 students had D's?