Debra Bishop's cabinet-making shope, in Des Moines, has five tools that automate the drilling of holes for the installation of hinges. These machines need setting up for each order of cabinets. The orders appear to follow the Poisson distribution, averaging 3 per 8-hour day. There is a single technician for setting these machines. Her service times are exponential, averaging 2 hours each.
a) What is the service factor for this system?
b) What is the average number of these machines in service?
c) What impact on machines in service would there be if a second technician were available?