I just need help with D and E

Consider two different machines A and B that could be used at a station. Machine A has a mean effective process time of 1.2 hrs and a Coefficient of variation of 0.5. Machine B has a mean effective process time of 0.8 hrs and a coefficient of variation of 1.5. a. c. For an arrival rate of 0.5 jobs per hour with Coeff. of variation of 1.1, which machine will have a shorter average flow time ? b. Now put 2 machines of type A at the station and double the arrival rate (this will double the capacity and double the throughput). What happens to the flow time? Do the same for machine B. Which type of machine produces the lower average flow time? d. With only one machine at the station, let the arrival rate be 0.6 jobs per hour with Coefficient of variation of 1.2, re-compute the average time spent at the stations for machine A and B. Compare the results to a. Consider the station with type of machine A. Let the arrival rate be 0.7 job per hour. What is the average time spent at the station? What happens to the average time spent at the station if the arrival rate is increased by 2%. e