Previous Paper Solution 2022

Operations Research


About This Paper

This page contains detailed solutions of MBA (QTM) – Operations Research Previous Year Question Paper 2022. All answers are written in simple and exam-oriented format suitable for 2 to 10 marks university questions.

University: Dr. A.P.J. Abdul Kalam Technical University (AKTU)
Course: MBA – Quantitative Techniques for Management (QTM)
Year: 2022

Important Topics Covered

This paper covers Linear Programming, Transportation Problem, Assignment Model, Game Theory, Queuing Theory, Replacement Model, CPM and Decision Tree Analysis.

Section A

1. State the Scope of Operations Research

Operations Research (OR) is a scientific approach to decision-making using mathematical models and analytical techniques.

Conclusion: OR helps in optimal use of limited resources in managerial decisions.

2. Define Uncertainty in Business

Uncertainty refers to a situation where future outcomes are unknown and probabilities cannot be assigned.

Example: Launching a new product without demand history.

Uncertainty increases risk and makes decision-making complex.

3. What is LPP in OR?

Linear Programming Problem (LPP) is a mathematical technique to maximize or minimize a linear objective function subject to linear constraints.

Example: Maximizing profit under labor and material constraints.

LPP ensures optimal allocation of resources.

4. Define Vogel’s Method in Transportation Problem

Vogel’s Approximation Method (VAM) is used to obtain an initial feasible solution for a transportation problem.

VAM generally gives a better initial solution than NW Corner method.

5. State about Assignment Model

The Assignment Model is a special case of transportation problem where one-to-one allocation is done.

Objective: Minimize cost or maximize profit.

Ensures optimal job allocation.

6. What is Two-Person Zero-Sum Game?

A competitive situation where gain of one player equals loss of the other.

Used in competitive business strategies.

7. What is Sequencing Problem in OR?

Sequencing problem determines the optimal order of jobs on machines to minimize total time.

Improves production efficiency.

8. Define Queue Model

A Queue Model studies waiting lines to minimize waiting time and service cost.

Example: Bank counter waiting system.

Balances service efficiency and cost.

9. What is Replacement Concept?

Replacement concept determines optimal time to replace equipment to minimize cost.

Helps reduce maintenance and breakdown cost.

10. Define CPM for Network

Critical Path Method (CPM) is a network technique used in project planning and control.

Ensures timely project completion.

Section B

Q2(a) Discuss Two Operations Research Methods to Solve Industrial Management Problems

Answer:

Operations Research (OR) provides scientific and quantitative techniques to solve complex industrial management problems. Two important OR methods widely used in industries are Linear Programming and Transportation Model.

1. Linear Programming (LP)

Linear Programming is a mathematical optimization technique used to maximize or minimize a linear objective function subject to linear constraints.

Basic Components of LP:

Industrial Applications:

Example: Agar factory ke paas limited labour hours aur raw material ho, LP determine karta hai kaunsa product kitna produce kare taki maximum profit mile.

Advantages:


2. Transportation Model

The Transportation Model is used to determine the least cost method of transporting goods from several sources to several destinations.

Objective: Minimize total transportation cost.

Methods Used:

Industrial Applications:

Example: Multiple factories se goods ko multiple warehouses tak bhejna at minimum transportation cost.

Conclusion: Linear Programming and Transportation models help industries reduce cost, increase efficiency and improve managerial decision-making.


Q2(b) Describe the Steps Involved in North-West Corner Method

Answer:

The North-West Corner Method (NWCM) is a technique used to obtain an Initial Basic Feasible Solution (IBFS) of a transportation problem.

Steps:

Step 1: Start from North-West Corner
Transportation table ke top-left cell se allocation start karo.

Step 2: Allocate Minimum of Supply and Demand
Allocation = min(Supply, Demand)
(Hinglish: jo value chhoti ho supply ya demand usko allocate kar do)

Step 3: Adjust Supply and Demand
Allocated quantity ko supply aur demand se subtract karo.

Step 4: Move to Next Cell
If supply becomes zero → move down.
If demand becomes zero → move right.

Step 5: Repeat the Process
Continue allocation until all supply and demand are satisfied.

Important Condition:
Total allocations must be = m + n − 1 (non-degenerate solution).

Limitation: This method ignores transportation cost, so it may not give optimal solution.


Q2(c) Explain Hungarian Algorithm for Assignment Problem

Answer:

The Hungarian Algorithm is used to solve assignment problems where the objective is to minimize cost or maximize profit.

Steps of Hungarian Method:

Step 1: Row Reduction
Har row ka smallest element find karo aur usko puri row se subtract karo.

Step 2: Column Reduction
Har column ka smallest element subtract karo.

Step 3: Cover All Zeros
Minimum number of horizontal and vertical lines draw karo to cover all zeros.

Step 4: Optimality Test
If number of lines = order of matrix → optimal solution found.
If not, smallest uncovered element subtract karke matrix adjust karo.

Step 5: Make Assignment
Independent zeros choose karo (ek row aur ek column me sirf ek assignment).

Advantages:

Conclusion: Hungarian method ensures minimum total cost assignment efficiently.


Q2(d) Applications of Johnson’s Algorithm for Sequencing Problem

Answer:

Johnson’s Algorithm is used for sequencing n jobs on two machines to minimize total elapsed time.

Conditions:

Procedure:

Applications:

Benefits:


Q2(e) What is Project Management? Discuss Drawing of Network Diagrams

Answer:

Project Management involves planning, scheduling and controlling activities to complete a project within specified time and cost limits.

Objectives:

Network Diagram:

A network diagram represents project activities and their relationships graphically.

Rules for Drawing Network:

Importance:

Conclusion: CPM and PERT are powerful tools in project management for effective planning and control.

Section B

Question 3

Q3(a) What are the Three Operations Research Techniques Used for Managerial Decision Making?

Answer:

Operations Research (OR) provides scientific and quantitative techniques that help managers take rational and optimal decisions. The three important OR techniques used in managerial decision-making are:


1. Linear Programming (LP)

Linear Programming is a mathematical optimization technique used to maximize or minimize a linear objective function subject to linear constraints.

Main Elements:

Managerial Applications:

Example: Agar ek company do products banati hai aur labour hours limited hain, LP determine karta hai kitna production kare taki maximum profit mile.

Importance:


2. Transportation and Assignment Models

Transportation Model: Used to minimize cost of distributing goods from multiple sources to multiple destinations.

Applications:

Assignment Model: Special case of transportation problem where one-to-one assignment is made.

Applications:

Importance: Reduces operational cost and improves efficiency.


3. Decision Theory / Decision Tree Technique

This technique is used when decisions are taken under conditions of certainty, risk, and uncertainty.

Applications:

Importance:

Conclusion: Linear Programming, Transportation/Assignment Models and Decision Tree techniques are powerful tools that enable managers to take scientific, cost-effective and optimal decisions.


Q3(b) Discuss Decision Tree Approach and Its Importance in Management

Answer:

A Decision Tree is a graphical representation of decision alternatives and possible outcomes including probabilities and payoffs. It is mainly used in decision-making under risk and uncertainty.


Components of Decision Tree


Steps in Decision Tree Analysis

Step 1: Define the problem clearly.

Step 2: Identify possible alternatives (e.g., launch product or not).

Step 3: Assign probabilities to different outcomes.

Step 4: Calculate Expected Monetary Value (EMV).

Formula:

EMV = Σ (Probability × Payoff)


Example:

A company is deciding whether to launch a new product.

EMV Calculation:

EMV = (0.6 × 5,00,000) + (0.4 × -2,00,000)
= 3,00,000 − 80,000
= ₹2,20,000

Since EMV is positive, launching the product is a better decision.


Importance of Decision Tree in Management

Conclusion: Decision Tree is a powerful managerial tool that helps in selecting the best alternative by evaluating probabilities and expected values systematically.

Question 4 – Linear Programming Problem

Q4(a) Solve the Following LPP by Graphical Method

Given:

Maximize

Z = 6L₁ + 11L₂

Subject to:

1) 2L₁ + L₂ ≤ 104

2) L₁ + 2L₂ ≤ 76

3) L₁ ≥ 0 , L₂ ≥ 0


Solution:

This Linear Programming Problem is solved using the Graphical Method because it contains only two decision variables.


Step 1: Convert Inequalities into Equations

2L₁ + L₂ = 104

L₁ + 2L₂ = 76

(Boundary lines draw karne ke liye inequality ko equal banate hain.)


Step 2: Find Intercepts

For 2L₁ + L₂ = 104

Points: (0,104) and (52,0)


For L₁ + 2L₂ = 76

Points: (0,38) and (76,0)


Step 3: Find Intersection Point

2L₁ + L₂ = 104 ...(1)
L₁ + 2L₂ = 76 ...(2)

Multiply equation (2) by 2:

2L₁ + 4L₂ = 152

Subtract equation (1):

3L₂ = 48

L₂ = 16

Substitute in (1):

2L₁ + 16 = 104

L₁ = 44

Intersection Point = (44,16)


Step 4: Corner Points of Feasible Region

Step 5: Calculate Z at Each Point

Z(0,0) = 0

Z(52,0) = 312

Z(0,38) = 418

Z(44,16) = 440


Final Answer:

Maximum Z = 440

L₁ = 44 , L₂ = 16

The optimal solution lies at the intersection point of the two constraints.

Q4(b) Explain Graphical Method of Solving Linear Programming Problem

Introduction:

The Graphical Method is used to solve Linear Programming Problems (LPP) when there are only two decision variables. It provides a visual representation of constraints and helps identify the optimal solution from the feasible region.


Conditions for Applying Graphical Method:


Steps in Graphical Method:

Step 1: Formulate the LPP

Define:

(Sabse pehle problem ko mathematical form me convert karte hain.)


Step 2: Convert Inequalities into Equations

Replace ≤ or ≥ signs with equal (=) sign to draw boundary lines.


Step 3: Plot Constraint Lines on Graph

Step 4: Identify Feasible Region

The feasible region is the common shaded area that satisfies all constraints.

(Ye area first quadrant me hota hai kyunki variables non-negative hote hain.)


Step 5: Find Corner (Extreme) Points

Determine coordinates of all intersection points of constraint lines.


Step 6: Evaluate Objective Function

Substitute each corner point into objective function.

The point giving maximum or minimum value is the optimal solution.


Advantages of Graphical Method:


Limitations:


Conclusion:

The Graphical Method is a fundamental technique in Linear Programming that helps managers determine the optimal solution visually by analyzing feasible region and corner points.

Question 5 – Assignment Model & Game Theory

Q5(a) Find the Optimal Solution of the Assignment Problem

Given Cost Matrix:

m1 → 12 8 7 8
m2 → 6 6 4 8
m3 → 3 5 7 4
m4 → 1 3 5 4

Solution Using Hungarian Method:

Step 1: Row Reduction

Har row ka smallest element subtract karte hain.

Step 2: Column Reduction

Ab har column ka smallest element subtract karte hain.

Step 3: Cover All Zeros

Minimum number of horizontal and vertical lines draw kiye to cover all zeros.

Since number of lines = 4 (order of matrix), optimal solution exists.

Step 4: Make Assignments

Independent zeros choose karte hain (ek row aur ek column me ek assignment).

Total Minimum Cost Calculation:

Total Cost = 8 + 4 + 4 + 1 = 17

Final Answer:

Optimal Assignment: m1–J2, m2–J3, m3–J4, m4–J1

Minimum Total Cost = 17


Q5(b) What is Game Theory? Discuss the Steps in Two-Person Zero-Sum Game

Meaning of Game Theory:

Game Theory is a mathematical technique used to study competitive situations where two or more players take strategic decisions.

In a Two-Person Zero-Sum Game, the gain of one player is equal to the loss of the other player.

Total payoff = Zero.


Key Characteristics:


Steps to Solve Two-Person Zero-Sum Game:

Step 1: Construct Payoff Matrix

Rows represent Player A strategies and columns represent Player B strategies.

Step 2: Apply Maximin Principle

Player A finds minimum payoff in each row and selects maximum among them.

Step 3: Apply Minimax Principle

Player B finds maximum payoff in each column and selects minimum among them.

Step 4: Check for Saddle Point

If Maximin = Minimax → Saddle point exists and pure strategy solution is obtained.

If not equal → Mixed strategy method is used.


Example:

B1 B2
A1 4 2
A2 3 5

Row minimums → 2 and 3 → Maximin = 3
Column maximums → 4 and 5 → Minimax = 4

Since Maximin ≠ Minimax, no saddle point exists.


Importance in Management:

Conclusion:

Game Theory provides a logical framework to analyze competitive situations and select optimal strategies.

Question 6 – Queuing Theory

Q6(a) Solve the Following Queuing Problem

Given Data:


Step 1: Convert Data into Standard Form

Arrival Rate (λ):

λ = 20 claims per 8 hours
λ = 20 / 8 = 2.5 claims per hour

Service Rate (μ):

Average service time = 40 minutes = 40/60 hours = 2/3 hour
μ = 1 / (2/3) = 1.5 per hour (per adjuster)

Total service rate (for 3 servers):

sμ = 3 × 1.5 = 4.5 per hour


(i) How Many Hours per Week Can an Adjuster Expect to Spend with Claimants?

Step 2: Calculate Utilization Factor (ρ)

ρ = λ / (sμ)
ρ = 2.5 / 4.5
ρ = 0.556

This means each adjuster is busy 55.6% of the time.

Step 3: Calculate Weekly Busy Hours

Working hours per week = 5 × 8 = 40 hours

Busy hours = 0.556 × 40 = 22.24 hours

Answer (i):

An adjuster spends approximately 22.24 hours per week attending claimants.


(ii) Average Time Spent by a Claimant in the Branch Office

Step 4: Calculate Average Time in System (W)

First find λ/s:
λ/s = 2.5 / 3 = 0.833

W = 1 / (μ − λ/s)

W = 1 / (1.5 − 0.833)
W = 1 / 0.667
W ≈ 1.5 hours

Answer (ii):

On average, a claimant spends approximately 1.5 hours in the branch office.


Q6(b) Discuss the Applications of Poisson Distribution in Queuing Model

Meaning of Poisson Distribution:

Poisson Distribution is used to describe the probability of a given number of arrivals occurring in a fixed time interval.

Formula:

P(x) = (e^−λ × λ^x) / x!

Where:


Applications in Queuing Model:


Example Calculation:

If average arrivals λ = 4 per hour, find probability of exactly 2 arrivals.

P(2) = (e^−4 × 4²) / 2!
= (e^−4 × 16) / 2
= 8e^−4


Importance in Queuing Theory:

Conclusion:

Poisson distribution plays a fundamental role in modeling random arrivals in queuing systems and helps in efficient service system design.

Question 7 – Replacement Model and CPM

Q7(a) Discuss Replacement of Assets Which Fail Suddenly

Introduction:

Replacement problems arise when machines, equipment or components become inefficient or fail. In case of sudden failure, items fail completely without prior warning.

Examples include electric bulbs, fuses, electronic parts and machine components.


Nature of Sudden Failure:


Replacement Policies:

1. Individual Replacement Policy
2. Group Replacement Policy

Decision Rule:

Compare:

The policy with minimum average cost is selected.


Advantages of Replacement Analysis:

Conclusion:

Replacement analysis helps management decide the most economical time and method for replacing assets that fail suddenly.


Q7(b) Find the Critical Path and Minimum Completion Time Using CPM

Given Data:


Precedence Relationships:


Step 1: Calculate Earliest Start (ES) and Earliest Finish (EF)

Activity v1:

ES = 0

EF = 0 + 10 = 10

Activity v2:

ES = 0

EF = 10

Activity v3:

Starts after 5 days of v1

ES = 5

EF = 5 + 6 = 11

Activity v4:

Depends on:

Maximum of (4, 8, 6) = 8

ES = 8

EF = 8 + 8 = 16

Activity v5:

Maximum = 10

ES = 10

EF = 10 + 12 = 22


Step 2: Determine Project Completion Time

Final activities finish at:

Project completion time = 22 days


Step 3: Identify Critical Path

The longest path is:

v1 → v5

Total Duration = 10 + 12 = 22 days


Final Answer:

Critical Path = v1 → v5

Minimum Completion Time = 22 days

Critical path activities have zero slack and determine the total project duration.