An automated car wash serves customers with the following serial process: pre-treat, wash, rinse, wax, hand dry. Each of these steps is performed by a dedicated machine except for the hand-dry step, which is performed manually on each car by one of three workers. The steps of the process have the following processing times:

• Pre-treat: 1 minute per car

• Wash: 5 minutes per car

• Rinse: 2 minutes per car

• Wax: 3 minutes per car

• Hand dry: 8 minutes per car

a. If the car wash has a demand of 15 cars per hour, what is the flow rate of the process?

b. If the car wash has a demand of 15 cars per hour, what is the utilization of the machine that performs the wax process?

 LO.1