Flow rate is = 15 cars/hour
Explanation:
For the flow rate of the process the following calculations are made:
hand dry: 14 minutes per car = 60 divided by14 = 4.29 cars/ hour (Rounded off)
(60 is the number of minutes in one hour)
but hand dry has 4 workers = 4.29 multiply by 4 = 17 cars/hour (Rounded off)
Pre-treat takes 4 minutes per car, rate = 60 divided by 4 = 15 cars/hour
wash takes 3 minutes per car, rate = 60 divided by 3 = 20 cars/hour
we do not need to check the other processes since the they all take less time than pre-treat
Flow rate is minimum of all = 15 cars/hour