Consider a train line at a bottleneck point over the course of an hour. If the average interarrival time is 10 minutes, the buffers are each 2.5 min, and the utilization is 0.8. Also consider a bus station at a local airport where each bus takes 10 minutes from the time it pulls in a space to the time it leaves the space. There are also five spaces available for the bus to park.

a) What is the average delay in minutes for arriving trains?

b)If the rail company would like a maximum average delay of 20 minutes, what should the utilization be kept under?

c) If the utilization is above 0.9, what is the level of service (or what are the levels of service if there are multiple possibilities)?