4. [20 points] These six jobs are to be scheduled on a single machine: Job 1 2 3 4 5 6 Processing Time (min.) 100 125 120 90 70 80 a. Suppose the jobs are processed in numerical order. Compute the average flowtime after each job is completed. b b. In what order would the jobs be processed using the SPT rule? Compute the average flowtime after each job is completed. Compare this answer with your answer to part (a).