Five administrative assistants use an office copier. The average time between arrivals for each assistant is 40 minutes, which is equivalent to an arrival rate of 1/40 = 0.025 arrival per minute. The mean time each assistant spends at the copier is 5 minutes, which is equiv- alent to a service rate of ¹⁄2 = 0.20 per minute. Use the M/M/1 model with a finite calling population to determine the following:

a. The probability that the copier is idle

b. The average number of administrative assistants in the waiting line

c. The average number of administrative assistants at the copier

d. The average time an assistant spends waiting for the copier

e. The average time an assistant spends at the copier

f. During an 8-hour day, how many minutes does an assistant spend at the copier? How much of this time is waiting time?

g. Should management consider purchasing a second copier? Explain.