$8.$ The following table shows orders to be processed at a machine shop as of $8$:$00$ a$.$m$.$ Monday. The jobs have different operations they must go through. Processing times are in days. Jobs are listed in order of arrival. a$.$ Determine the processing sequence at the first work center using each of these rules: $(1)$ FCFS$,(2)$ S$/$O$.$ b$.$ Compute the effectiveness of each rule using each of these measures: $(1)$ average flow time, $(2)$ average number of jobs at the work center.