Must show work: A clerk at the local coffee shop takes about 4 minutes to process each order (according to a negative exponential distribution). Her customers typically arrive at a rate of 12 every hour. Her shop is small, and only has room to hold three customers waiting in line. She wants to wait on her customers in 10 minutes or less. Use Table D.5 and Little's Law to answer these questions. [Note that lambda and mu are not in the same units (one is in hours and one is in minutes); you need to convert one of them so that they are in the same units, such as hours.]

a) (Reminder to state the queue model) Does she have enough room in her shop for the typical waiting line?

b) Is she meeting her service objective?

c) If she adds another clerk to serve coffee, how does this impact the waiting time of the customers, and her customer service objectives? (Use calculations to support your answer!)