Question

# A 3. The jobs listed below needed to be completed. Assume that it is now day 140. Job Processing Time (days) Due Date 20 180 30 с 10 175 16 230 E 18 210 B 200 D 1:54 If the jobs are sequenced according to shortest processing time rule, what is the average completion time! A. 47.6 B. 60 C. 50 D. 238 E 300 4. Given the data from question 3, if the jobs are sequenced according to the longest processing time rule, what is the lateness of job B? A. O B. 24 C. 7.4 D. 9 E 13.4

Answer 1

3)

Considering that jobs are started on day 140, so day 140 is the first working day for these jobs.

F A B с D E 1_3) Shortest Processing Time rule Jobs are scheduled in ascending order of their processig time 2 3 4 Starting day: 140 5 6 16 7 8 9 10 11 12 Job C D E A B Processing Time (days) Due Date Completion Time Lateness 10 175 10 -26 230 26 -65 18 210 44 -27 20 180 64 23 30 200 94 33 Average = 47.6 -12.4 13 14

EXCEL FORMULA:

F А В с D E 1 3 Shortest Processing Time rule 2 Jobs are scheduled in ascending order of their processig time 3 4 Starting day: 140 5 6 7 8 9 10 11 12 Job Processing Time (days) Due Date Completion Time Lateness C 10 175 =C7 =E7+$F$4-D7-1 D 16 230 =E7+C8 =E8+$F$4-08-1 E 18 210 =E8+C9 =E9+$F$4-09-1 A 20 180 =E9+C10 =E10+$F$4-D10-1 B 30 200 =E10+C11 =E11+$F$4-D11-1 Average = =AVERAGE(E7:E11) -AVERAGE(F7:F11) 13 14

Average completion time:  A. 47.6

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4)

Schedule based on longest processing time rule, is following:

F G 1 A B с D E 3 Longest Processing Time rule Jobs are scheduled in descending order of their processig time 2 3 4 Starting day: 140 5 6 7 oc Job B A E D 20 9 Processing Time (days) Due Date Completion Time Lateness 30 200 30 -31 180 50 9 18 210 68 -3 16 230 84 -7 10 175 94 58 Average = 65.2 5.2 с 10 11 12 13 14

EXCEL FORMULAS remain same as for part (3)

Lateness of job B = D. 9