Question: For the previous problem about the coffee dispenser, consider a new machine that is faster on average: with it the average service time is 25 seconds per cup. But service time varies a little; the standard deviation of service time is 5 seconds per cup. Compare this machine to the original one. Determine:

a. The average number of customers waiting in line.

b. The average time customers spend in the system.

c. The average number of customers in the system.

d. The average cost per hour of the system if the operating costs of the machine are $20 per hour and the cost of waiting is estimated to be $30 per hour