Help w/ ONLY PART d (explain how to get from given question to given answer):

USC football jerseys are in high demand. The process of manufacturing the jerseys is as follows.

• To produce the jerseys, raw material is first cut into cloths for individual jerseys. This step requires 1 minute on average for each jersey and there are three separate machines available for this task.
• After the cloth is cut, the player number and last name are printed on the jerseys. There are three printing machines, each of which can print on one jersey in 45 seconds.
• The printed jersey is then reviewed and packaged by a quality control worker. On average, this takes 90 seconds per jersey, but the standard deviation of this inspection step is 2 minutes. There are five quality control employees for this task.
• Orders for jerseys arrive at exponentially distributed intervals, with an average of 160 orders per hour. From beginning to end, the average time to produce one jersey is 4.5 minutes

a). Find the capacity at each resource. ANSWER: Capacity A = 180 jerseys per hour, Capacity B = 240 jerseys per hour, Capacity C = 200 jerseys per hour

b). On average, there are 8/3 = 2.6667 jerseys at the cutting step and 7.21 jerseys at the inspection step. How many jerseys are on average in the printing step? ANSWER: 2.12 jerseys

c. (4 points) To reduce average wait time, the factory wants to reduce the utilization of the inspection workers to 4/7 = 57.14%. How many total workers should there be at the inspection step in order to achieve this? ANSWER: 7 workers

d. Under the new staffing derived in (c), what is the new average waiting time (in minutes) at the inspection step? CORRECT ANSWER: 0.13 min