Question 4 (15 pts). A shuttle bus operates between the Virgin Beach and a hotel. Due to unpredictable trafc situation, the return times are distributed uniformly over the interval from 20 minutes to one hour. Assume that they are independent of each other. The time the bus stays at the Virgin Beach (including disembarkation and embarkation) is negligible. (a) (8 pts) Compute the long-term number of arrivals of the bus per hour. (b) (7 pts) What is the long-term number of arrivals of the bus per hour instead, if the return times are distributed uniformly over the interval from 30 mins to one hour instead