The jobs listed below needed to be completed. Assume that it is now day 140. If the jobs are sequenced according to shortest processing time rule, what is the average completion time?
A) 47.6 days
B) 60.2 days
C) 94.0 days
D) 2.5 days
E) 238.0 days

Question

The jobs listed below needed to be completed. Assume that it is now day 140. If the jobs are sequenced according to shortest processing time rule, what is the average completion time? 
A) 47.6 days 
B) 60.2 days 
C) 94.0 days 
D) 2.5 days 
E) 238.0 days

Quizplus · Accepted Answer

Using the shortest processing time rule, we first order the tasks in ascending order of processing time:

Task 2 - 2 days
Task 1 - 3 days
Task 4 - 5 days
Task 3 - 7 days
Task 5 - 11 days

We then calculate the average completion time using the following formula:

(Processing time of Task 1 + Processing time of Task 2 + ... + Processing time of Task n)/n

= (3 + 2 + 5 + 7 + 11)/5

= 28/5

= 5.6

Adding this to the starting day (day 140), we get:

140 + 5.6 = 145.6

Therefore, the average completion time is 145.6 days, which is closest to answer choice A (47.6 days).

The Jobs Listed Below Needed to Be Completed