The owner/operator of the local franchise of Handyman, Inc., has four jobs to do today, shown in the order they were received: $$\begin{array} { c c c }
\text { Job } & \begin{array} { c }
\text { Processing Time } \
\text { (hrs) }
\end{array} & \begin{array} { c }
\text { Due } \
\text { (hrs from now) }
\end{array} \
\text { W } & 4 & 4 \
\mathrm { X } & 3 & 5 \
\mathrm { Y } & 2 & 2 \
\mathrm { Z } & 1 & 1
\end{array}$$
If he uses the shortest processing time first priority rule to schedule these jobs, what will be the average number of jobs in his shop today?
A) 0
B) 1
C) 2
D) 3
E) 4

Question

The owner/operator of the local franchise of Handyman, Inc., has four jobs to do today, shown in the order they were received: $$\begin{array} { c c c } 
\text { Job } & \begin{array} { c } 
\text { Processing Time } \
\text { (hrs) }
\end{array} & \begin{array} { c } 
\text { Due } \
\text { (hrs from now) }
\end{array} \
\text { W } & 4 & 4 \
\mathrm { X } & 3 & 5 \
\mathrm { Y } & 2 & 2 \
\mathrm { Z } & 1 & 1
\end{array}$$
If he uses the shortest processing time first priority rule to schedule these jobs, what will be the average number of jobs in his shop today?
A) 0
B) 1
C) 2
D) 3
E) 4

Quizplus · Accepted Answer

Using the shortest processing time first priority rule, the owner/operator will start with job Z with a processing time of 1 hour. After completing Z, he will start working on job Y with a processing time of 2 hours. By this time, job W and X will have reached their due time, so he will have to start working on them without delay. He will be able to complete job W with a processing time of 4 hours, but he will still be working on job X when it is due in 5 hours. Therefore, the average number of jobs in his shop today will be (1 + 2 + 3 + 2)/4 = 2 jobs. Therefore, the best choice is C.

The Owner/operator of the Local Franchise of Handyman, Inc If He Uses the Shortest Processing Time First Priority Rule