A crew of mechanics at the Highway Department Garage repair vehicles that break down at an average of = 8 vehicles per hour (approximately Poisson in nature). The mechanic crew can service an average of = 11 vehicles per hour with a repair time distribution that approximates an exponential distribution. The crew cost is approximately $300 per hour. The cost associated with lost productivity from the breakdown is estimated at $150 per vehicle per hour. Which is cheaper, the existing system with one service crew, or a revised system with two service crews (with two service crews, assume multiple-server system)? How is .8381 calculated for the multi-service waiting cost?