Prelim- Operations Research- Paper A
Solve both sections. Solve any 3 questions from section 2
Section 1
Q1. Explain the following concepts (3X5=15)
- Closed loop in transportation
- Decision tree
- Resource constrains in LPP
- Updating in networking
- Degeneracy in simplex
Q2. The following information is available for a network. Indirect cost id Rs 300 per day. Time give is in days (15 marks)
Job |
1—2 |
1–3 |
2—3 |
2–4 |
2–5 |
3–6 |
4–5 |
5–6 |
Normal time |
9 |
15 |
7 |
7 |
12 |
12 |
6 |
9 |
Normal cost |
1300 |
1000 |
1000 |
1200 |
1700 |
600 |
1000 |
900 |
Crash time |
4 |
13 |
4 |
3 |
6 |
11 |
2 |
6 |
Crash cost |
2400 |
1380 |
1540 |
1920 |
2240 |
700 |
1600 |
1200 |
Draw the network diagram and find the critical path and corresponding cost. What would be the impact on the cost if the deadline of 27days is imposed?
Section 2 (solve any 3. 10 marks each)
Q3. A company manufactures two products A and B. Profit per unit of A and B are Rs 3, 5 respectively. Each unit of A and B requires 3 and 2 units of labour hours. The company has a maximum of 18 labour hours available. Also the maximum demand for A and B is limited to 4 and 6 units respectively. Formulate the above as LPP and solve by simplex.
Q4. The following cost, demand and supply information is available. Optimise the transport cost. No units can be transferred from P2 to M1. Would a 50% discount on route P3-M3 have an impact on the solution
Plant/Market    M1        M2        M3        Supply
P1Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 6Â Â Â Â Â Â Â Â Â Â Â Â Â 9Â Â Â Â Â Â Â Â Â Â Â Â Â 8Â Â Â Â Â Â Â Â Â Â Â Â Â 120
P2Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â –Â Â Â Â Â Â Â Â Â Â Â Â Â 4Â Â Â Â Â Â Â Â Â Â Â Â Â 2Â Â Â Â Â Â Â Â Â Â Â Â Â 80
P3Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 11Â Â Â Â Â Â Â Â Â Â 5Â Â Â Â Â Â Â Â Â Â Â Â Â 4Â Â Â Â Â Â Â Â Â Â Â Â Â 80
Demand              150        70          60
Q5. Consider the problem of assigning 4 clerks to 4 tasks. Time in hours taken by each is given below.
 |
Tasks |
|||
Clerks | A | B | C | D |
I |
4 |
7 |
5 |
6 |
II |
3 |
8 |
7 |
4 |
III |
3 |
5 |
5 |
3 |
IV |
6 |
6 |
4 |
2 |
Clerk II cannot be assigned A and Clerk III cannot be assigned B. Find the optimum allocation.
How do you find out that an alternate solution exists in the assignment sum.
Q6.A. For the following data compute EMV, EPPI, EVPI and EOL (4 marks)
Probability |
S1 |
S2 |
S3 |
S4 |
S5 |
0.1 |
20 |
12 |
4 |
-4 |
-12 |
0.2 |
20 |
22 |
14 |
6 |
-2 |
0.4 |
20 |
22 |
24 |
16 |
8 |
0.2 |
20 |
22 |
24 |
26 |
18 |
0.1 |
20 |
22 |
24 |
26 |
28 |
B. A company is planning to buy a machine at Rs 50,000. It is anticipated that if the machine is purchased the demand can go up and hence the revenues gained would be Rs 75,000. If the demand is not good there is a loss of Rs 20,000. The company feels that there are 70% chances that demand being good and 30% chances of a bad demand. Construct a decision tree and help the company decide whether the machine should be purchased or no. (6 marks)
Prof Vipin Saboo can be contacted on 9820779873 for any further clarifications.
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