NATIONAL OPEN UNIVERSITY OF NIGERIA FACULTY OF SOCIAL SCIENCES DEPARTMENT OF ECONOMICS 2018_1 EXAMINATION
COURSE TITLE: OPERATIONS RESEARCHCOURSE CODE: ECO 314
UNITS:2
TIME ALLOWED: 2 HOURS
INSTRUCTIONS: ANSWER THREE QUESTIONS
QUESTION 1
A firm produces an alloy having the following specifications:
(i)specific gravity≤0.98,
(ii)chromium≥8%,
(iii)melting point≥450°C.
Raw materials A, B and C having the properties show ninth table can be used to make the alloy.
Property
|
Properties of raw material
|
|
|
|
|
|
|
|
A
|
B
|
C
|
|
|
|
|
Specific gravity
|
0.92
|
0.97
|
1.04
|
Chromium
|
7%
|
13%
|
16%
|
Melting point
|
0
|
0
|
o
|
|
440C
|
490C
|
480C
|
Costs of the various raw materials pert on are:#90 for A,#280 for B and #40 for
C.Formulate the L.P model to find the proportions in which A,B and C be used to obtain analoy of desired properties while the cost of raw materials is minimum.
(Total Mark=20%)
QUESTION 2
What conditions must be satisfied before linear programming can be used for
optimization problems?
(6Mark)
List and explain the assumptions in linear programming models. (11 Mark)
(Total Mark=17%)
QUESTION 3
Define operations research. (3 Mark)
Discuss the scope of operations research in financial management. (8 Mark)
List the various schemes by which models can be classified. (6 Mark)
(Total Mark=17%)
QUESTION 4
What are the most popular priority rules for job sequencing?(8 Mark)
What are the components of inventory carrying cost? (9 Mark)
(Total Mark=17%)
QUESTION 5
Assuming eight jobs are waiting to be processed. The processing time and due
dates for the jobs are given below:
JOB
|
PROCESSING TIME
|
DUE DATE(DAYS)
|
|
|
|
A
|
4
|
9
|
|
|
|
B
|
10
|
18
|
|
|
|
C
|
6
|
6
|
|
|
|
D
|
12
|
19
|
|
|
|
E
|
7
|
17
|
|
|
|
F
|
14
|
20
|
|
|
|
G
|
9
|
24
|
|
|
|
H
|
18
|
28
|
|
|
|
Determine the sequence processing according to First Come,First Serve (FCFS)
in the light of the following criteria:
Average flow time
Average number of jobs in the system
Average job lateness
Utilization of the workers.
(17 Mark)