Table J.16
Five jobs are currently waiting to be processed. Each job has to go through Machine 1 first and then Machine 2 before it is completed. The processing times (in hours) for the five jobs on each machine are:

-Use the information in Table J.16. What is the makespan through both machines if the SPT rule is used to determine the sequence at Machine 1 and the same sequence is also used at Machine 2?
A) fewer than or equal to 27 hours
B) greater than 27 hours but fewer than or equal to 28 hours
C) greater than 28 hours but fewer than or equal to 29 hours
D) greater than 29 hours

Question

Table J.16
Five jobs are currently waiting to be processed. Each job has to go through Machine 1 first and then Machine 2 before it is completed. The processing times (in hours) for the five jobs on each machine are:
 
-Use the information in Table J.16. What is the makespan through both machines if the SPT rule is used to determine the sequence at Machine 1 and the same sequence is also used at Machine 2?
A) fewer than or equal to 27 hours 
B) greater than 27 hours but fewer than or equal to 28 hours 
C) greater than 28 hours but fewer than or equal to 29 hours 
D) greater than 29 hours

Quizplus · Accepted Answer

The Shortest Processing Time (SPT) rule prioritizes jobs based on their processing times, starting with the shortest. When applied to Machine 1 and the same sequence is used for Machine 2, the makespan (total completion time through both machines) will be optimized but not necessarily minimized for the entire system. Without specific job times, we can't calculate the exact makespan, but following the SPT rule generally leads to efficient use of machines and reduced waiting times, suggesting a makespan that is efficient but without the exact job times or the table data, a precise calculation isn't possible. The choice indicates a makespan that is efficient, acknowledging the effectiveness of the SPT rule without providing a specific duration.

Table J.16 Five Jobs Are Currently Waiting to Be Processed. Each Job