Six patients are waiting in a hospital emergency room to receive care for various complaints, ranging from a sprained ankle to a gunshot wound. The patients are numbered in the sequence that they arrived and are given a priority weighting based on the severity of the problem. There is only one doctor available.

Patient 1 2 3 4 5 6 Time required 20 min 2 hr 30 min 10 min 40 min 1 hr Priority 1 10 3 5 2 2

a. Suppose that the patients are scheduled on an FCFS basis. Compute the mean flow time and the weighted mean flow time, where the weight is the priority number associated with each patient.

b. Perform the calculations in part

(a) for SPT sequencing.

c. Determine a sequence different from those in parts

(a) and

(b) that achieves a lower value of the weighted mean flow time.