Question

The Hickory Company manufactures wooden desks. Management schedules overtime every weekend to reduce the backlog on the most popular models. The automatic routing machine is used to cut certain types of edges on the desktops. The following orders need to be scheduled for the routing​ machine:

order	time arrived hours	estimated machine hours	due date hours
1	1	9	20
2	0	7	21
3	6	8	12
4	5	3	8
5	3	12	18

The due dates reflect the need for the order to be at its next operation. Develop separate schedules by using the FCFS and EDD rules. Compare the schedules on the basis of average flow time and average past due hours.

A. Using the FCFS​ (first come, first served​ ) decision rule for sequencing the​ orders, the order​ is

Sequence	1	2	3	4	5
order	3	4	5	1	2

B Using the EDD​ (earliest due​ date) decision rule for sequencing the​ orders, the order is​ (to resolve a​ tie, use order in which the orders were​ received):

Sequence	1	2	3	4	5
Order	4	3	5	1	2

C. The average flow time and average past due hours for each option are ​(enter your responses are real numbers rounded to two decimal

​places)​:

Rule	Average Flow Time	Average Past Due Hours
EDD
FCFS

Answer 1

(A) Using the FCFS (First come first serve) rule, the optimal sequence is 3-4-5-1-2

(B) Using the EDD (Earliest Due Date) rule, the optimal sequence is 4-3-5-1-2.

(C) Given that most famous model requires overtime. So model 5 will require ovetime of 12 hours

STEP 1: EVALUATION FOR FCFS RULE::

Job	Process time	Flow time	Due Date	Lateness
3	8	0+8 = 8	12	--
4	3	8+3 = 11	8	3
5	12	11+12 = 23	18	5
1	9	23+9 = 32	20	12
2	7	32+7 = 39	21	18

Total flow time = (8+11+23+32+39)+12

Total flow time = 125

Numner of jobs = 5

Average flow time = 125/5 = 25 hours

Average past due hours = Total lateness/ Number of jobs

Average past due hours = (3+5+12+18)/5

Average past due hours = 7.6

(B) EVALUATION FOR EDD RULE::

Job	Process time	Flow time	Due Date	Lateness
4	3	0+3 = 3	8	--
3	8	3+8 = 11	12	--
5	12	11+12 = 23	18	5
1	9	23+9 = 32	20	12
2	7	32+7 = 39	21	18

Total flow time = (3+11+23+32+39)+12

Total flow time = 120

Numner of jobs = 5

Average flow time = 120/5 = 24 hours

Average past due hours = Total lateness/ Number of jobs

Average past due hours = (5+12+18)/5

Average past due hours = 7