1. Cars and trucks arrive at Sparkle Auto Wash, a single-channel service facility, at a mean rate of 9.60 per hour. The service takes an average of 4.5 minutes per vehicle (including asking customers what level of wash they want and collecting payment) with the current equipment, staffing level, and operating procedures. The interarrival times and service times are distributed according to a negative exponential distribution.

a. What is the utilization of the facility?

b. What is the average number of vehicles in line waiting to get into the service area?