Trucks are arriving to a warehouse on an average rate of 1

Operations Management Nov 18, 2020

Trucks are arriving to a warehouse on an average rate of 1.2 per hour. A single crew consisting of two workers can unload a truck in 30minutes on average. Both arrival and service rates follow Poisson distribution. Each crew member receives a wage of $40 per hour. The waiting truck driver and driver together reflect upon an hourly cost of $60. The manager is thinking of an optimum crew size to unload.
What is the optimum crew size?