A Print Shop Has Five Large Commercial Printing Jobs to Finish

A print shop has five large commercial printing jobs to finish. They are trying to decide whether to use the shortest processing time (SPT) or the first come, first served (FCFS) sequencing rule. Data on estimated processing time (in hours) and time to promised completion (in hours) is as follows (jobs shown in order of arrival):
$\begin{array}{|c|c|c|}\hline \text { Job } & \text { Processing time } & \text { Time to promised completion } \\\hline \text { A } & 4 & 8 \\\hline \text { B } & 9 & 30 \\\hline \text { C } & 5 & 17 \\\hline \text { D } & 8 & 8 \\\hline \text { E } & 11 & 12 \\\hline\end{array}$
a.What is the average flow time in hours using the FCFS rule?
b.What is the average job lateness in hours using the FCFS rule?
c.What is the average flow time in hours using the SPT rule?
d.What is the average job lateness in hours using the SPT rule?