are these correct ? can you help me understand the work

An automated car wash serves customers with the following serial process: pretreat, 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: Pretreat 3 minute per car Wash: 7 minutes per car Rinse: 3 minutes per car Wax 3 minutes per car Hand dry: 6 minutes per car Round Flow rate" and "Utilization of hand dry" and "Cycle time" to 2 decimal places a. Which resource is the bottleneck of this process? Wash 8.57 customers per hour Round your answer to 2 decimal places. b. If the car wash has a demand of 20 cars per hour, what is the flow rate of the process? Round your answer to 2 decimal places. If the car wash has a demand of 20 cars per hour, what is the utilization of the machine that performs the Wax process? Round your answer to 2 decimal places. d. If the car wash has a demand of 6 cars per hour, what is the utilization of hand dry? 4285 percent C. percent Round your answer to 2 decimal places If the car wash has a demand of 6 cars per hour, what is the cycle time of the process (minutes)? 11.87 minutos 64 minutes Round your answer to nearest whole number Now assume demand is 20 cars per hour. Starting from an empty system (and assuming the stations can work independently), how long would it take (minutes) to wash 4 cars? f