A crew of mechanics at the Highway Department garage repair vehicles that break down at an average of = 8 vehicles per day (approximately

A crew of mechanics at the Highway Department garage repair vehicles that break down at an average of λ = 8 vehicles per day (approximately Poisson in nature). The mechanic crew can service an average of μ = 11 vehicles per day with a repair time distribution that approximates an exponential distribution. The crew cost is approximately $300 per day. The cost associated with lost productivity from the breakdown is estimated at $150 per vehicle per day.
a. If there is currently one service crew, what is the expected number of vehicles in the system?

b. If we add another service crew, what is the expected number of vehicles in the system?

c. Which is cheaper, the existing system with one service crew, or a revised system with two service crews?