5.20. A dealer sells 20 vehicles each week. 80% of all purchasers of a vehicle buy a service package provided by the dealership. a. (Fill in the blank) The number of service packages sold at the dealership is expected to be around , give or take b. What is the probability that the dealership will sell 15 to 18 (inclusive) service packages? c. What is the probability that the dealership will sell at most 15 service packages? d. What is the probability that the dealership will sell 15 service packages