68% of all students at a college still need to take another math class. If 32 students are randomly selected, find the probability that a. Exactly 21 of them need to take another math class. b. At most 21 of them need to take another math class. c. At least 20 of them need to take another math class. d. Between 19 and 27 (including 19 and 27) of them need to take another math class. Hint