PROBLEM 1: Suppose that all car owners fill up when their tanks are exactly half full. At the present time, an average of 7.5 customers per hour arrives at a single-pump gas station. It takes an average of 4 minutes to service a car. Assume that inter-arrival times and service times are both exponential. (a) What is the arrival rate? The service rate? The utilization? (b) Hand-compute the average number of cars at the station. (c) Hand-compute the average time (in minutes) a car spends at the station. (a) Use EXCEL Macro to verify your answer to parts ( a ) and (c)