DEPARTMENT OF MECHANICAL...

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DEPARTMENT OF MECHANICAL ENGINEERING QUESTION BANK VIII SEMESTER ME6015OPERATIONS RESEARCH Regulation 2013 Academic Year 2016 17

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DEPARTMENT OF

MECHANICAL ENGINEERING

QUESTION BANK

VIII SEMESTER

ME6015– OPERATIONS RESEARCH

Regulation – 2013

Academic Year 2016 – 17

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DEPARTMENT OF MECHANICAL ENGINEERING

QUESTION BANK

SUBJECT : ME6015 – OPERATIONS RESEARCH

SEM / YEAR : VIII Semester / IV Year MECH

UNIT I LINEAR MODELS

The phase of an operation research study – Linear programming – Graphical method– Simplex algorithm – Duality

formulation – Sensitivity analysis..

PART - A

Q.No Questions BT Level Competence

1. Define Operations Research (OR). 1 Remember

2. Define Linear Programming problem. 1 Remember

3. List the four assumptions in Linear programming 1 Remember

4. Define Big M method. 1 Remember

5. Differentiate between simplex and Big M Method. 2 Understand

6. What is Two phase method? 1 Remember

7. What do you mean by Duality? List the Rules for primal and dual. 1 Remember

8. Compare Slack variable and Surplus Variable. 2 Understand

9. Distinguish between Feasible and Optimal solution. 2 Understand

10. Summarize the Graphical method procedure. 2 Understand

11. Discuss about sensitivity analysis. 2 Understand

12. Give some example for usage of Surplus variable & Slack Variable. 3 Apply

13. Point out the application areas of LPP 4 Analyze

14. Give two examples for objective solutions 3 Apply

15. Demonstrate the unbounded solution of LP problems graphically. 3 Apply

16. Explain the limitations of LPP. 4 Analyze

17. What do you think about Infeasible solution? 4 Analyze

18. Criticize why the two phase method is better than big M method? 5 Evaluate

19. Analyze the difference between unrestricted and artificial variables. 4 Analyze

20. Generalize the maximization LPP with an example. 6 Create

PART - B

1. Maximise Z=3x+4y subject to

2x+5y ≤ 60,

4x+2y ≤ 40.

x, y >=0. Solve by Graphical Method and find the optimal solution. (16)

1

Remember

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2. Write the dual of the following LPP and solve it. Find the best value for x & y.

Maximize Z = 4 X1 +2 X2

Subject to the constraints - X1 – X2 ≤-3

- X1 + X2 ≥ -2 , X1, X2 ≥ 0

(16)

1

Remember

3. i) List out the graphical method Procedure to solve simple linear programming

problems of two decision variables. (4)

ii) Examine the following LP problem using graphical method

Minimize Z = 2 X1 + 3 X2

Subject to

X1 + X2 ≥6,

7 X1 + X2 ≥14

X1 and X2 ≥ 0. (12)

1

1

Remember

Remember

4. i) Compare minimization problem and maximization problem in LPP. (4)

ii) Analyze the following LPP by Simplex Method:

Max Z= 3x1+2x2

Subject to 2x1+x2 ≤ 2,

3x1+4x2 ≥ 12,

3x1+4x2 ≤ 0 &

x1,x2 ≥ 0. (12)

4

4

Analyze

Analyze

5. Evaluate by using dual simplex method solve the LPP.

Minimize Z=2x+y

Subject to 3x+2y ≥ 3

4x+3y ≥ 6

x+y ≤ 5 & x , y ≥ 0 (16)

5

Evaluate

6. A company manufactures two types of products P1, P2.Each product uses lathe

and Milling machine. The processing time per unit of P1 on the lathe is 5 hours

and on the milling machine is 4 hours. The processing time per unit of P2 on the

lathe is 10 hours and on the milling machine, 4 hours. The maximum number of

hours available per week on the lathe and the milling machine are 60 hours and

40 hours, respectively. Also the profit per unit of selling P1 and P2 are Rs.6.00

and Rs.8.00, respectively. Create a linear programming model to determine the

production volume of each of the products such that the total profit is maximized.

and also solved by simplex method. (16)

6

Create

7. Use simplex method to calculate X1 and X2 in the LPP.

Maximize Z = 4X1 + 10X2

Subject to the constraints

2X1 + X2 ≤ 50

2X1 + 5X2 ≤ 100

3

Apply

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2X1 + 3X2 ≤ 90 and

X1, X2 ≥ 0. (16)

8. Analyze the dual of the following LPP and solve it. Find the value of x1 & x2.

Maximize Z = 4x1+2x2

Subject to the constraints -x1-x2 ≤-3

-x2+x2 ≥-2 , x1, x2 ≥ 0 (16)

4

Analyze

9. A company produces 2 types of hats A & B. Every hat B requires twice as much

as labour time as hat A. The company can produce a total of 500 hats a day. The

market limits daily sales of the A & B to 150 and 250 hats respectively. The

Profits on hats A & B are Rs..8 & Rs.5 respectively. Construct a Simplex table

and solve it. (16)

2

Understand

10. a) Explain slack variable and surplus variable. (4)

b) Develop a Simplex Table and Solve

Max Z = 3 x1+2 x2, Subject to x1+ x2 ≤4,

x1- x2 ≤ 2; x1, x2 ≥0.. (12)

4

6

Analyze

Create

11. An animal feed company must produce 200 Kg of a mixture consisting of

ingredients x1 & x2 respectively x1 cost Rs.3 per kg and x2 cost Rs.8 per kg. not

more than 80 Kg of x1 can be used and atleast 60 Kg of x2 must be used.

Determine how much of each ingredient must be used to minimize cost.

3

Apply

12. i) What is meant by linear programming problem? Give brief description of the

problem with illustrations. How the same can be solved graphically. What are the

basic characteristics of a linear programming problem? (8)

ii) Solve the following LPP Graphically:

Minimize Z = 4X1 + 3X2

Subject to the constraints

X1 + 3X2 ≥ 9

2X1 + 3X2 ≥ 12

X1 + X2 ≥ 5

X1, X2 ≥ 0. (8)

2

3

Understand

Apply

13. A company produces refrigerator in Unit I and heater in Unit II. The two products

are produced and sold on a weekly basis. The weekly production cannot exceed

25 in unit I and 36 in Unit II, due to constraints 60 workers are employed. A

refrigerator requires 2 man week of labour, while a heater requires 1 man week of

labour, the profit available is Rs. 600 per refrigerator and Rs. 400 per heater.

Formulate the LPP problem and solve by any method. (16)

5

3

Evaluate

Apply

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14. Formulate the dual of the following primal problem and Examine this problem.

Maximize Z = 4x1 + 10x2 + 25x3

Subject to

2x1 + 4x2 + 8x3 ≤ 25,

4x1 + 9x2 + 8x3 ≤ 30

6x1 + 8x2 + 2x3 ≤ 40

x1, x2, and x3 ≥ 0. (16)

6

Create

UNIT II - TRANSPORTATION MODELS AND NETWORK MODELS

Transportation Assignment Models –Traveling Salesman problem-Networks models – Shortest route – Minimal spanning tree

– Maximum flow models –Project network – CPM and PERT networks – Critical path scheduling – Sequencing models.

PART - A

Q.No Questions BT Level Competence

1. List out the common methods to obtain an initial basic feasible solution for a

transportation problem.

1 Remember

2. Define optimality test in a transportation problem. 1 Remember

3. Quote the differences between North west corner rule and minimum matrix

method.

1 Remember

4. Differentiate balanced transportation problem from unbalanced transportation

problem.

2 Understand

5. Describe unbounded assignment problem. 1 Remember

6. Define transshipment problem. 1 Remember

7. What difference exist between Transportation & Transshipment Problems? 2 Understand

8. Where assignment problems are used? 1 Remember

9. Describe how a maximization problem is solved using assignment model. 1 Remember

10. Illustrate the traveling salesman problem. 3 Apply

11. Distinguish between CPM and PERT. 2 Understand

12. Give the mathematical formulation of assignment problem. 2 Understand

13. Describe the method of processing ‘n’ jobs through two machines. 1 Remember

14. Illustrate any sequencing model with your own example. 3 Apply

15. Compare pessimistic time with optimistic time. 4 Analyze

16. How to measure the free float of an activity in a network. 5 Evaluate

17. Compare Vogel approximation method (VAM) & Least Cost Method. 4 Analyze

18. Explain the purpose of using dummy activities in a network with an example. 5 Evaluate

19. Summarize the assumptions, based on which PERT/CPM analysis is done for a

project.

5 Evaluate

20. Generalize the mathematical formulation of transportation problem. 6 Create

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PART - B

1. i) Write the steps involved for solving Transportation problem using Vogel’s

Approximation method. (8)

ii) Obtain the Initial Basic Feasible Solution for the following TP using North

West Corner method.

I II III Supply

S1 8 5 6 120

S2 15 10 12 80

S3 3 9 10 150

Demand 150 80 50

(8)

1

3

Remember

Apply

2. Solve the following assignments problem

I II III IV V

A 10 5 9 18 11

B 13 19 6 12 14

C 3 2 4 4 5

D 18 9 12 17 15

E 11 6 14 19 10

(16)

3

Apply

3. Solve the TP where cell entries are unit costs. Use vogel’s approximate method to

find the initial basic solution

D1 D2 D3 D4 D5 AVAIL

ABLE

O1 68 35 4 74 15 18

O2 57 88 91 3 8 17

O3 91 60 75 45 60 19

O4 52 53 24 7 82 13

O5 51 18 82 13 7 15

REQUI

RED 16 18 20 14 14

(16)

4

Analyze

4. Solve the following travelling salesman problem so as to minimize the cost per

cycle. Determine whether path is satisfied.

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TO

A B C D E

A - 3 6 2 3

B 3 - 5 2 3

FROM C 6 5 - 6 4

D 2 2 6 - 6

E 3 3 4 6 -

(16)

5

Evaluate

5. Solve the following transportation problem to maximize the profit.

(16)

2

Understand

6. Five workers are available to work with the machines and respective cost

associated with each worker –machine assignments is given below. A sixth

machine is available to replace one of the existing machines and the associated

costs are also given below.

Determine whether the new machine can be accept and also determine optimal

assignments and the associated saving in cost. (16)

5

Evaluate

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7. Solve the assignment problem given below.

(16)

2

5

Understand

Evaluate

8. A small project is composed of seven activities whose time estimates are listed in

the table as follows

Activity Preceding

activities Duration

A --- 4

B --- 7

C --- 6

D A,B 5

E A,B 7

F C,D,E 6

G C,D,E 5

i) Draw the network and find the project completion time. (8)

ii) Calculate the three floats for each activity. (8)

5

Evaluate

9. Calculate the

total float, (4)

free float and (4)

independent float for the project whose activities are given below: (4)

Activity 1-2 1-3 1-5 2-3 2-4 3-4 3-5 3-6 4-6 5-6

Time

(mins) 8 7 12 4 10 3 5 10 7 4

Find the critical path also. (4)

4

Analyze

10. A small project is composed of 7 activities, whose time estimates are listed in the

table below. Activities are identified by their beginning (i) and (j) node numbers.

i) Draw the project network and identify all the paths through it. (4)

ii) Find the expected duration and variance for each activity. What is the

expected project length? (4)

iii) Calculate the variance and standard deviation of the project length. What

is the probability that the project will be completed at least 4 weeks earlier

than expected time? (8)

2

Understand

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11. The following table lists the jobs of a network along with their time estimates.

Draw the network. Calculate the length and variance of the critical path and find

the probability that the project will be completed within 30 days. (16)

5

Evaluate

12.

Use graphical method to minimize the time needed to process the following jobs

on machines A, B, C and D. Find the total time to complete the jobs.

JOB1 Sequence A B C D

Time (hrs) 2 3 5 2

JOB2 Sequence D C A B

Time (hrs) 6 2 3 1

(16)

6

Create

13.

Develop the optimal sequence of jobs that minimizes the total elapsed time

required to complete the following jobs and find the total elapsed time. The jobs

are to be processed on three machines M1, M2 and M3 in the order M1 – M2 –

M3.

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JOB M1 M2 M3

A 3 4 6

B 8 7 3

C 7 2 5

D 4 5 11

E 9 1 5

F 8 4 6

G 7 3 12

(16)

6

Create

14. Evaluate the sequence that minimizes the total elapsed time (hours) to complete

the following jobs on two machines M1 and M2 in the order M1 – M2. Find also

the idle time.

JOB M1 M2

A 5 2

B 1 6

C 9 7

D 3 8

E 10 4

(16)

5

Evaluate

UNIT III - INVENTORY MODELS

Inventory models – Economic order quantity models – Quantity discount models – Stochastic inventory models – Multi

product models – Inventory control models in practice.

PART - A

Q.No. Questions BT Level Competence

1. Define inventory. 1 Remember

2. List out the basic inventory models. 1 Remember

3. Name the various costs involved in inventory problems. 1 Remember

4. Define safety stock. 1 Remember

5. When the inventory can be increased? Why? 1 Remember

6. Express the disadvantages of increased inventory. 2 Understand

7. Differentiate direct inventory from indirect inventory. 2 Understand

8. Summarize the causes of poor inventory control. 2 Understand

9. Give explanation for lead time and reorder point. 2 Understand

10. Classify types of Inventories. 3 Apply

11. Show the economic order quantity graphically. 3 Apply

12. Identify when shortage cost and stock out cost arises. 3 Apply

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13. Highlight the importance of Reorder level. 4 Analyze

14. What inference can you make about holding cost? 4 Analyze

15. Discuss the concept of Quantity Discount Model 5 Evaluate

16. Contrast EOQ and EBQ. 4 Analyze

17. Explain the Monte Carlo Method. 5 Evaluate

18. Compare Ordering Cost and Carrying Cost. 5 Evaluate

19. Summarize the objectives of inventory control. 5 Evaluate

20. Interpret the meaning of EOQ 6 Create

PART - B

1. Alpha industry needs 5400 units per year of a bought out component which will

be used in its main product. The ordering cost is Rs.250 per order and the

carrying cost per unit per year is Rs.30. Which is the best order quantity and

Number of order per year and Frequency of orders? (16)

1

Remember

2. A stockiest has to supply 12000 units of a product per year to his customer.

Demand is fixed and known. Shortage cost is assumed to be infinite. Inventory

holding cost is 20 paise per unit per month. Ordering Cost is Rs. 250 and

purchase price is Rs.10 per unit. Develop EOQ & Frequency of orders and total

inventory cost. (16)

2

Understand

3. Demand for an item in a company is 18,000 units per year. The company can

produce the items at a rate of 3000 units per month. The Cost of one setup is

Rs.500 and the holding cost of one unit per month is 15 paise. Shortage cost of

one unit is Rs.20 per year. Analyze and find the optimum manufacturing quantity

and number of shortage, frequency of Production run. (16)

4

Analyze

4. A company has a demand of 12000 units per year for an item and it can produce

2000 such items per month. The cost of one setup is Rs400 and holding

cost/unit/month is Rs.0.15. Find the optimum lot size and total cost per year,

assuming the cost of one unit as Rs.4. Also find the maximum inventory,

manufacturing time and total time. (16)

3

Apply

5. A contractor has to supply 10000 bearings per day to an automobile

manufacturer. He finds that when he starts a production run he can produce 25000

bearings per day. The cost of holding a bearing in stock for one year is 2 paise

and the set up cost of the production run is Rs.18. How frequently should

production run be made and which is the Best Economic Batch Quantity? How

much would be the No. of Setup and Total Inventory Cost. (16)

4

Analyze

6. A stockiest has to supply 400 units of a product every Monday to his customer.

He gets the product at Rs.50 per unit from the manufacturer. The cost of ordering

and transportation from the manufacturer is Rs.75 per order. The cost of carrying

inventory is 7.5% per year of the cost of product. Predict EOQ, Frequency of

orders and Number of Orders, Total Incremental cost and Total Cost. (16)

4

Analyze

7. A company uses annually 50000 units of an item each costing Rs1.20. Each order

costs Rs.45 and inventory carrying cost are 15 % of average annual inventory

value.

i) Find the Economic order quantity. (4)

2

2

Understand

Understand

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ii) If the company operates 250 days an year, the procurement time is 10

days and safety stock is 500 units, find the reorder level, maximum,

minimum and average inventory. (12)

8. i) Explain the inventory model with price break. (4)

ii) A company requires 200 casting per month. The requirement is assumed

to be fixed and known. The set up cost per procurement is Rs. 350. The

holding cost is 2% of the cost of the item. The price break details are as

follows.

K11 = Rs. 10 /- 0 < q < 500

K12 = Rs 9.50 /- q >=500

Find the optimal purchase quantity. (12)

4

5

Analyze

Evaluate

9. i) Explain the inventory models with probabilistic demand. (6)

ii) Find the various results for the following inventory model.

Demand rate = 10000 units/year

Production rate = 20000 units/year

Setup cost = Rs. 400/-

Holding cost = Rs 1.60/- per unit/year

Shortage cost = Rs 18/- per unit/year. (10)

4

5

Analyze

Evaluate

10. i) ABC manufacturing company purchases 9000 parts of a machine for its

annual requirement. Each part costs Rs.20. The ordering cost per order

is Rs.15 and the carrying charges are 15% of the average inventory per

year. Apply EOQ formulae and find out the Total Inventory Cost. (8)

ii) A company has a demand of 12000 units/year for an item and it can

produce 2000 units per month. The cost of one setup is Rs.400 and the

holding cost/unit/month is 15 paise. Select the optimum lot size and total

cost per year assuming the cost of 1 unit as Rs.4. Find EBQ (8)

4

Analyze

11. i) Classify and explain various inventory models. (6)

ii) An air craft company uses a certain part at a constant rate of 2500 units

per year. Each unit costs Rs 30/- and the company personnel estimate

that it costs Rs.130/- to place an order and carrying cost is 10% per year.

How frequently should orders be placed? Determine the optimum size of

each order. (10)

4

5

Analyze

Evaluate

12. A textile industry has a demand of 8000 drive pulleys per year. The cost of one

procurement is Rs. 100/- and the holding cost per unit is Rs. 2.25 per year. The

replacement is instantaneous and no shortages are allowed. Evaluate

i) The EOQ (4)

ii) The number of orders per year (4)

iii) The time between orders (4)

iv) The total cost per year if the cost of one unit is Rs 1.50. (4)

5

Evaluate

13. i) Derive the simplest economic order quantity formula. State all the

assumptions. (6)

ii) A company uses 25000 units of an item each costing Rs 2/-. Each order

2

Understand

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cost Rs.120/- and inventory carrying cost are 12% of the average annual

inventory value. Find EOQ. If the company operates 300 days an year,

the procurement time is 15 days and safety stock is 350 units, find the

reorder level, maximum, minimum and average stock. (10)

3

Apply

14. Find the optimal order quantity for a product for which the price breaks are as

follows.

K11 = Rs. 12.50 0 < q < 750

K12 = Rs. 11.75 750 <= q < 1500

K13 = Rs. 11.00 q >= 1500 (16)

5

Evaluate

UNIT IV - QUEUEING MODELS

Queueing models - Queueing systems and structures – Notation parameter – Single server and multi server models – Poisson

input – Exponential service – Constant rate service – Infinite population – Simulation.

PART - A

Q.No Questions BT Level Competence

1. Define Kendal’s notation for representing queuing models. 1 Remember

2. How would you explain consumer behaviour? 1 Remember

3. List out the basic elements of queue. 1 Remember

4. Define a queue. Give example. 1 Remember

5. Distinguish between transient and steady state queuing system 4 Analyze

6. What are the assumptions in m/m/1 model? 3 Apply

7. Give the formula for the problem for a customer to wait in the system under

(m/m/1 : N/FCFS)?

2 Understand

8. Identify the properties of Poisson process. 4 Analyze

9. Categorize Queue Discipline. 3 Apply

10. Compare Serial and parallel Queue with Examples. 2 Understand

11. Classify the service disciplines. 3 Apply

12. Differentiate single channel queue and multi-channel queue. 3 Apply

13. Interpret the terms arrival rate and service rate in queuing models. 6 Create

14. Give the formulae for expected number of customers in the queue and the system

for (M/M/1): (FCFS/∞/∞)

4 Analyze

15. Write down the postulates of birth and death process? 3 Apply

16. Describe Kendall’s Notation for identifying a Queue Model with two channels,

Poisson arrivals, exponential service and infinite calling population.

1 Remember

17. In a super market, the average arrival rate of customer is 5 in every 30 minutes

following Poisson process. The average time is taken by the cashier to list and

calculate the customer’s purchase is 4.5 minutes; following exponential

distribution. What is the probability that the queue length exceeds 5?

5 Evaluate

18. If traffic intensity of M/M/I system is given to be 0.76, what percent of time the

system would be idle?

5 Evaluate

19. Interpret the Characteristics Of Queuing Models. 6 Create

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20. Customer arrives at a one-man barber shop according to a Poisson process with

an mean inter arrival time of 12 minutes. Customers spend a average of 10

minutes in the barber’s chain.What is the expected no of customers in the barber

shop and in the queue?

6 Create

PART - B

1. A self-service store employs one cashier at its counter. 9 Customers arrive on an

average every 5 minutes. While the cashier can serve 10 customer in 5 minutes.

Assuming Poisson Distribution for arrival rate and exponential distribution for

service

rate Find the following:

(i) Average number of customer in the system

(ii) Average Number of customer in Queue.

(iii) Average time a customer spend in the system

(iv) Average time a customer wait before being Served. (16)

4

Analyze

2. A super market has 2 girls running up sales at the counters. If the service time for

each customer is exponential with mean of 4 minutes and if people arrive in a

Poisson fashion at the rate of 10 an hour. Infer the following:

(i) What is the average waiting time a customer spends in the system?

(ii) What is the expected percentage of Idle time for each girl? (16)

4

Analyze

3. A two – person barber shop has five chairs to accommodate waiting customers.

Potential customers who arrive when all five chairs are full leave without entering

the barbershop. Customers arrive at the average rate of 3.7674 per hour and spend

an average of 15 minutes is the barber chair. Apply Kendall’s Notation and Solve.

i) What is the probability a customer can get directly into the barber chair upon

arrival?

ii) What is the effective arrival rate?

iii) How much time can a customer expect to spend in the barber shop?

iv) How much time can a customer expect to spend in the barber shop? (16)

5

Evaluate

4. In a reservation counter with a single server, customer arrive with the inter-arrival

time as the exponential distribution with mean 10 minutes. The service time is

also assumed to be exponential with mean 8 minutes. Find

i) the idle time of the server

ii) the average length of the Queue.

iii) Expected time that a customer spends in the system. (16)

2

Understand

5. Ships arrive at a port at the rate of one in every 4 hours with exponential

distribution of inter arrival times. The time a ship occupies a berth for unloading

has exponential distribution with an average of 10 hours. If the average delay of

ships waiting for berths is to be kept below 14 hours. How many berths should be

provided at the port?

3

Apply

6. A branch of a national bank has only one typist. Since the typing work varies in

length, the typing rate is randomly distributed approximating Poisson distribution

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with mean rate of 8 letters per hour. The letter arrives at a rate of 5 per hour

during the entire 8 hour work day. If the typewrite is valued at Rs.1.50 per hour.

Determine equipment utilization, the percent time an arriving letter has to wait,

average system time and average idle time cost of the typewriter per day. (16)

3 Apply

7. i) Explain any two queuing models with example. (4)

ii) If, for a period of 2 hours in a day trains arrive at the yard every

20minutes but the service time continues to remain 36 minutes.

Calculate the probability that the yard is empty and average queue

length on the assumption that the time capacity of the yard is limited to

4 trains only. (12)

4

5

Analyze

Evaluate

8. i) Write a short note on M/M/1 models and their applications. (4)

ii) Patients arrive at a clinic according to poissons distribution at the rate of

30 per hour. The waiting room does not accommodates more than 14

patients. Examination time per patient is exponential with mean rate of

20 per hour. Find the effective arrival rate at the clinic. What is the

expected waiting time of a patient until he is discharged? (12)

2

3

Understand

Apply

9. Arrivals of a telephone booth are considered to be poisson with an average time

of 10 minutes between one arrival and the next. The length of phone call is

assumed to be distributed exponentially, with mean 3 minutes.

i). What is the probability that a person arriving at the booth will have to wait? (6)

ii). The telephone department will install a second booth when convinced that an

arrival would expect waiting for atleast 3 minutes for a phone call. By how much

should the flow of arrivals increase in order to justify a second booth? (6)

iii). What is the average length of the queue that forms from time to time? (4)

3

Apply

10. An airport emergency medical facility has a single paramedic and room for a total

of three patients, including the one being treated. Patients arrive with an

exponentially distributed inter arrival time with a mean of one hour. Service time

is exponentially distribute with a mean of 30 minutes.

i). What percentage of the time is the paramedic busy? (8)

ii). How many patients on average are refused entry in a 24 hour day? (4)

iii). What is the average number of patients in the facility at any given time? (4)

4

Analyze

11. An insurance company has three claims adjusters in its branch office. People with

claims against the company are found to arrive in a Poisson fashion, at an average

rate of 20 per 8 hour day. The amount of time that an adjuster with a claimant is

found to have an exponential distribution, with mean service time 40 minutes.

Claimants are processed in the order of their appearance.

i). How many hours a week an adjuster expected to spend with claimants? (8)

ii). How much time, on the average, does a claimant spend in the branch office?

(8)

5

Evaluate

12. A bank has two tellers working on savings accounts. The first teller handles

withdrawals only. The second teller handles depositors only. It has been found

that the service time distributions of both depositors and withdrawals are

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exponential with a mean service time of 3 minutes per customer. Depositors and

withdrawers are found to arrive in a Poisson fashion throughout the day with

mean arrival rate of 16 and 14 per hour.

i). What would be the effect on the average waiting time for depositors and

withdrawers if each teller could handle both withdrawals and deposits? (8)

ii). What would be the effect if this could only be accomplished by increasing the

service time to 3.5 minutes. (8)

5

Evaluate

13. A departmental store has a single cashier. During the rush hours customers arrive

at a rate of 20 customers per hour. The average number of customers that can be

processed by the cashier is 24 per hour. Assume that the conditions for use of the

single channel queuing model apply.

i). What is the probability that the cashier is idle? (4)

ii). What is the average number of customers in the queuing system? (4)

iii). What is the average time a customer spends in the system? (4)

iv). What is the average number of customers in the queue? (4)

4

Analyze

14. At a certain filling station, customers arrive in a Poisson process with an average

time of 12 per hour. The time intervals between services follow exponential

distribution and as such the mean time taken to service a unit is 2 minutes.

Evaluate:

i). the probability that there is no customer at the counter. (4)

ii). the probability that there are more than two customers at the counter. (4)

iii). the probability that there is no customer to be served. (4)

iv). the expected number of customers waiting in the system. (4)

5

Evaluate

UNIT V - DECISION MODELS

Decision models – Game theory – Two person zero sum games – Graphical solution- Algebraic solution– Linear

Programming solution – Replacement models – Models based on service life – Economic life– Single / Multi variable search

technique – Dynamic Programming – Simple Problem.

PART - A

Q.No Questions BT Level Competence

1. Compile the Characteristics of game. 1 Remember

2. How would you make use of the concept of Game theory in Managerial Decision

Making?

3 Apply

3. Interpret the concept of two person zero sum game. 6 Create

4. How decision Tree analysis is related to improve the decision-making process? 1 Remember

5. Identify the basic assumptions of the Game. 3 Apply

6. Conclude the advantages of Game theory. 4 Analyze

7. Summarize how graphs and LP solution are used in Game theory. 2 Understand

8. What is a Decision Tree? 1 Remember

9. Define Dominance principle. 1 Remember

10. Classify the different types of strategy. 4 Analyze

11. Classify the types of Replacement model. 4 Analyze

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12. Explain saddle point and value of game shortly. 4 Analyze

13. Point out the limitations of game theory. 4 Analyze

14. Compare competitive game and rectangular game. 4 Analyze

15. Point out the situations which make replacement necessary. 1 Remember

16. Define group replacement. Give example. 1 Remember

17. Explain dynamic programming problem. 4 Analyze

18. Differentiate linear programming from dynamic programming. 4 Analyze

19. Give the applications of dynamic programming. 2 Understand

20. Compare single and multi-variable search techniques. 4 Analyze

PART - B

1. The cost of machine is Rs.16,100 and scrap value is Rs.1,100. Maintenance Cost

form for machine are as follows:

Year 1 2 3 4 5 6 7 8

Cost 300 450 600 800 100 1200 1500 2000

When should the machine be the replaced? (16)

1

Remember

2. The following table gives to cost of spares per year, overhead cost of maintenance

per year and resale value of certain equipment whose purchase price is Rs.

50,000: Illustrate when the machine can be replaced.

Year 1 2 3 4 5

Cost of spares 10000 12000 14000 15000 17000

Overhead

cost 5000 5000 6000 6000 8000

Resale value 40000 32000 28000 25000 22000

(16)

3

Apply

3. A Taxi owner estimates from his past records that the cost per year for operating a

taxi whose purchase price when new is Rs.60,000 are as follows.

Age 1 2 3 4 5

Operating

cost 10000 12000 15000 18000 20000

After 5 years the operating cost is Rs.6000 x K, Where “k” is 6,7,8,9,10(age). If

the resale value decreases by 10% of purchase price each year, what is the best

replacement policy if time value is not implemented? (16)

3

Apply

4. i) Deduce an expression for the average annual cost of an item over a

period of n years, when the money value remains constant. (6)

ii) A truck has been purchased at a cost of Rs.1,60,000. The value of the

truck is depreciated in the first 3 years by Rs 20,000 each year and Rs

16,000 per year thereafter. Its maintenance and operating cost for the

first 3 years are Rs 16000, 18000 and 20000 in that order and then

increase by Rs 4000 every year. Assuming an interest rate of 10% find

the economic life of the truck. (10)

6

4

Create

Evaluate

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5. Machine A Costs Rs.9000. Annual Operating Cost is Rs.200 for the 1st year and

then increases by 2000 every year. Determine the best age at which to replace the

machine. Assume the machine has no resale value.

Machine B Costs Rs.10,000 . Annual operating cost is Rs.400 for the 1st year and

then increases by 800 every year. No resale value. You have now a machine of

type A which is one year old. Conclude if M/c A can be replaced by M/c B. Is so,

When? (16)

1

Remember

6. i) Explain Bellman’s principle of optimality and give classical formulation

and the dynamic programing formulation of any problem. (8)

ii) State the principle of optimality in dynamic programming. Explain the

basic features which characterize a dynamic programming problem. (8)

4

Analyze

7. i) Explain decision tree analysis with example. (6)

ii) In a game of matching coins with 2 players, A wins 1 unit value when

there are 2 heads, wins nothing when there are 2 tails and closes ½ unit

value when there are one head and one tail. Determine Pay Off matrix

and value of the game. (10)

5

Evaluate

8. i) Two players A&B match coins. If the coins match then A wins one unit

value, if the coins do not match then B wins one unit of value.

Determine pay-off matrix which strategy is to be chosen and find the

value of game. (8)

ii) A and B play a Match(Game) in which each has 3 coins 5 paise, 10 paise

and 20 paise. Each player selects a coin without the knowledge of others

choice. IF the sum is even, B wins A’s Coin. Find the Best Strategy &

value of the Game. (8)

2

Understand

9. i) Using dominance rule solve the following game.

(8)

ii) Solve the following 3 x 3 game by the method of matrices.

1 -1 -1

-1 -1 3

-1 2 -1

(8)

3 2 4 0

3 4 2 4

4 2 4 0

0 4 0 8

3

Apply

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10. Solve the following game

Player B

Pla

yer

A

1 2 3 4 5

1 3 5 4 9 6

2 5 6 3 7 8

3 8 7 9 8 7

4 4 2 8 5 3

(16)

3

Apply

11. i) Differentiate the decision making under risk and under uncertainty in

statistical decision theory. (4)

ii) Using graphical method, solve the following game and evaluate the

game value.

B1 B2 B3 B4

A1 2 2 3 -2

A2 4 3 2 6

(12)

2

5

Understand

Evaluate

12. An electro mechanical equipment has a purchase price of Rs 7000/-. Its resale

value and running cost are given here.

Year 1 2 3 4 5 6 7 8

Running

cost 2000 2100 2300 2600 3000 3500 4100 4600

Resale

value 4000 3000 2200 1600 1400 700 700 700

When to replace the machine? (16)

1

Remember

13. The cost of a machine is Rs.6100/- and its scrap value is Rs 100/-. The

maintenance costs found from experience are as follows.

Year 1 2 3 4 5 6 7 8

Maintenance

cost 100 250 400 600 900 1200 1600 2000

When should the machine be replaced? (16)

1

Remember

14. Write short notes on

i) Economic life (4)

ii) Decision models (4)

iii) Dynamic programming (4)

iv) Two persons zero sum games (4)

2

Understand