A crew of mechanics at the Highway Department garage repair vehicles that break down at an average of 3 vehicles every 12 minutes (approximately Poisson in nature). The mechanic crew can service an average of 3 vehicles every 10 minutes with a repair time distribution that approximates an exponential distribution. The crew cost is approximately $150 per hour. The cost associated with lost productivity from the breakdown is estimated at $50 per hour.  Which is cheaper, the existing system with one service crew or a revised system with two service crews? Note that the average waiting time for adding the second crew is 0.01.