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LP PROBLEMS FOR PRACTICE BY GIRISH PHATAK Q.1 A manufacturing company is engaged in producing three types of products: A, B and C. The production department produces, each day, components sufficient to make 50 units of A, 25 units of B and 30 units of C. The management is confronted with the problem of optimizing the daily production of products in assembly department where only 100 man hours are available daily to assemble the products. The following additional information is available. Type of product Profit contribution per unit of product (Rs) Assembly time per product (hrs) A 12 0.8 B 20 1.7 C 45 2.5 The company has a daily order commitment for 20 units of product A and a total of 15 units of products B and C. Formulate this problem as an LP model so as to maximize the total profit. Q.2 A company has two plants, each of which produces and supplies two products A and B. The plants can each work up to 16 hours a day. In plant 1, it takes three hours to prepare and pack 1,000 gallons of A and one hour to prepare and pack one quintal of B. In plant 2, it takes two hours to prepare and pack 1,000 gallons of A and 1.5 hours to prepare and pack one quintal B. In Plant 1 it costs Rs. 15,000 to prepare and pack a thousand gallons of A, and RS. 28,000 to prepare and pack a quintal of B, whereas these costs are Rs 18,000 and Rs 26,000, respectively in plant 2. The company is obliged to produce daily at least 10 thousand gallons of A and 8 quintals of B. Formulate this problem as an LP model to find out as to how the company should organize its production so that the required amounts of the two products be obtained at minimum cost. Q.3 An electronic company is engaged in the production of two components C 1 and C 2 used in radio sets. Each unit of C 1 costs the company Rs 5 in wages and RS 5 in material, while each of C 2 costs the company Rs 25 in wages and RS 15 in material. The company sells both products on one period credit terms, but the company’s labour and material expenses must be paid in cash. The selling price of C 1 is Rs 30 per unit and of C 2 it is Rs 70 per unit. Because of the strong monopoly of the company for these

Linear Programming Problems-2010

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Page 1: Linear Programming Problems-2010

LP PROBLEMS FOR PRACTICE BY GIRISH PHATAK

Q.1 A manufacturing company is engaged in producing three types of

products: A, B and C. The production department produces, each day,

components sufficient to make 50 units of A, 25 units of B and 30 units of

C. The management is confronted with the problem of optimizing the daily

production of products in assembly department where only 100 man – hours

are available daily to assemble the products.

The following additional information is available.

Type of product Profit contribution per

unit of product (Rs)

Assembly time per

product (hrs)

A 12 0.8

B 20 1.7

C 45 2.5

The company has a daily order commitment for 20 units of product A

and a total of 15 units of products B and C. Formulate this problem as an LP

model so as to maximize the total profit.

Q.2 A company has two plants, each of which produces and supplies two

products A and B. The plants can each work up to 16 hours a day. In plant 1,

it takes three hours to prepare and pack 1,000 gallons of A and one hour to

prepare and pack one quintal of B. In plant 2, it takes two hours to prepare

and pack 1,000 gallons of A and 1.5 hours to prepare and pack one quintal

B. In Plant 1 it costs Rs. 15,000 to prepare and pack a thousand gallons of A,

and RS. 28,000 to prepare and pack a quintal of B, whereas these costs are

Rs 18,000 and Rs 26,000, respectively in plant 2. The company is obliged to

produce daily at least 10 thousand gallons of A and 8 quintals of B.

Formulate this problem as an LP model to find out as to how the

company should organize its production so that the required amounts of the

two products be obtained at minimum cost.

Q.3 An electronic company is engaged in the production of two components

C1 and C2 used in radio sets. Each unit of C1 costs the company Rs 5 in

wages and RS 5 in material, while each of C2 costs the company Rs 25 in

wages and RS 15 in material. The company sells both products on one –

period credit terms, but the company’s labour and material expenses must be

paid in cash. The selling price of C1 is Rs 30 per unit and of C2 it is Rs 70

per unit. Because of the strong monopoly of the company for these

Page 2: Linear Programming Problems-2010

components, it is assumed that the company can sell at the prevailing prices

as many units as it produces. The company’s production capacity is,

however, limited by two considerations. First, at the beginning of period ,

the company has an initial balance of Rs 4,000 (cash plus bank credit plus

collections from past credit sales). Second, the company requires production

of each C1 , 2 hours of machine time and 2 hours of assembly time, whereas

the production of each C2 requires 2 hours of machine time and 3 hours of

assembly time. Total machine time available is 2000 hrs whereas total

assembly time available 1400 hrs in the given period. Formulate this

problem as an LP model so as to maximize the total profit to the company.

Q.4 A company has two grades of inspectors 1 and 2, who are to be assigned

for a quality control inspection. It is required that at least 2,000 pieces be

inspected per 8 hour day. Grade 1 inspector can check pieces at the rate of

40 per hour, with an accuracy of 97 per cent. Grade 2 inspector checks at the

rate of 30 pieces per hour with an accuracy of 95 per cent.

The wage rate of a Grade 1 inspector is Rs 5 per hour while that of a

Grade 2 inspector is Rs 4 per hour. An error made by an inspector costs Rs 3

to the company. There are only nine Grade 1 inspectors and eleven Grade 2

inspectors available in the company. The company wishes to assign work to

the available inspectors so as to minimize the total cost of the inspection.

Formulate this problem as an LP model so as to minimize daily inspection

cost.

Q.5 An electronic company produces three types of parts for automatic

washing machines. It purchases casting of the parts from a local foundry and

then finishes the part on drilling, shaping and polishing machines.

The selling prices of parts A, B and C, respectively are Rs 8, Rs 10

and Rs 14. All parts made can be sold. Castings for parts A, B and C,

respectively cost Rs 5, Rs 6 and Rs 10.

The shop possesses only one of each type of machine. Costs per hour

to run each of the three machines are Rs 20 for drilling, Rs 30 for shaping

and RS 30 for polishing. The capacities (parts per hour) for each part on

each machine are shown in the following table :

Machine Capacity per hour

Part A Part B Part C

Drilling 25 40 25

Page 3: Linear Programming Problems-2010

Shaping 25 20 20

Polishing 40 30 40

The management of the shop wants to know how many parts of each

type it should produce per hour in order to maximize profit for an hour’s run.

Formulate this problem as an LP model so as to maximize total profit to the

company.

Q.6 A pharmaceutical company produces two pharmaceutical products. A

and B. Production of both products requires the same process, I and II. The

production of B results also in a by – product C at no extra cost. The product

A can be sold at a profit of Rs 3 per unit and B at a profit of Rs 8 per unit.

Some of this by – product can be sold at a unit profit of Rs 2, the remainder

has to be destroyed and the destruction cost is Re 1 per unit. Forecasts show

that up to 5 units of C can be sold. The company gets 3 units of C for each

unit of B produced. The manufacturing times are 3 hours per unit for A on

process I and II, respectively, and 4 hours and 5 hours per unit for B on

process I and II, respectively. Because the product C results from producing

B, no time is used in producing C. The available times are 18 and 21 hours

of process I and II, respectively. Formulate this problem as an LP model to

determine the quantity of A and B which should be produced, keeping C in

mind, to make the highest profit to the company.

Q.7 A tape recorder company manufacturers models A, B and C which have

profit contributions per unit of Rs 15, Rs 40 and RS 60, respectively. The

weekly minimum production requirements are 25 units for model. A, 130

units for model B and 55 units for model C. Each type of recorder requires a

certain amount of time for the manufacturing of component parts, for

assembling and for packing. Specifically a dozen units of model A require 4

hours for manufacturing, 3 hours for assembling and 1 hour for packaging.

The corresponding figures for a dozen units of model B are 2.5, 4 and 2 and

for a dozen units of model

Q.8 ABC company manufactures three grades of paint Venus, Diana and

Aurora. The plant operates on a three – shift basis and the following data is

available from the production records :

Requirment

of resource

Grade Venus Diana Aurora Availability

(capacity/month)

Page 4: Linear Programming Problems-2010

Special

additive

(kg/litre)

0.30 0.15 0.75 600 tonnes

Milling

(kilolitres per

machine

shift)

2.00 3.00 5.00 100 machine

shifts

Packing

(kiloliters per

shift)

12.00 12.00 12.00 80 shifts

There are no limitations on other resources. The particulars of sales forecasts

and estimated contribution to overheads and profits are given below.

Venus Diana Aurora

Maximum

possible sales per

month (kilolitres)

100 400 600

Contribution

(Rs/kilolitre)

4,000 3,500 2,000

Due to commitments already made, a minimum of 200 kiloliters per

month of Aurora has to be necessarily supplied the next year.

Just as the company was able to finalise the monthly production

programme for the next 12 months, an offer was received from a nearby

competitor for hiring 40 machine shifts per month of milling capacity for

grinding Dianna paint, that could be spared for at least a year. However, due

to additional handling at the competitor’s facility, the contribution from

Dianna will get reduced by Re 1 per litre.

Formulate this problem as an LP model for determining the monthly

production programme to maximise contribution.

Q.9 A garment manufacturer has production line making two styles of shirts. Style 1

require 200 grams of cotton thread, 300 grams of dacron thread, and 300 grams of liner

thread. Style II require 200 grams of cotton thread, 200 grams of dacron thread and 100

gram of liner thread. The manufacturer make the net profit of Rs. 19.50 on Style I ,Rs.

15.90 on Style II. He has in hand inventory of 24kg. Of cotton thread ,26kg of dacron

thread, and 22 kg of liner thread. His immediate problem is to determine the production

Page 5: Linear Programming Problems-2010

schedule given the current inventory to make a maximum profit. Formulate the LPP

Model

Q.10 A firm makes two types of furniture: Chairs and tables. The contribution of each

product as calculated by accounting department is Rs. 20 Per chair and Rs 30 per table.

Both products are processed on three machines M1,M2 and M3.The time required by

each product and total time available per week on each machine are as follow:

Machine Chair Table Available Hours

M1 3 3 36

M2 5 2 50

M3 2 6 60

How should the manufacturer his production in order to maximize contribution?

Q.11 The ABC manufacturing company can make two products p1 and p2.Each of the

product requires time on a cutting machine and a finishing machine. Relevant data are:

P1 P2

Cutting Hours(Per Unit) 2 1

Finishing Hours(Per Unit) 3 3

Profit (Rs. Per unit) 6 4

Maximum Sales(Unit Per

Week)

200

The number of cutting hours available per week is 390 and number of finishing

hours available per week is 810.How much should be produced of each product in order

to achieve the profit for the company?

Q.12 A company make two kinds of leather belts. Belt A is a high quality belt, and belt B

is of low quality. The respective profits are re.0.40 and re.30 per belt. Each belt of type A

requires twice as much time as a belt of type B, and if all belts were of type B, the

company could make 1000 per day. The supply of leather is sufficient for only 800 belts

per day (both A & B combined). But Belt A requires a fancy buckle & only 400 per day

are available. T here are only 700 buckles a day available for belt B.

What should be the daily production of each type of belt? Formulate the LPP.

First Topic Linear Programming Problems for Practice

PROBLEM 1:

XYZ factory manufactures two articles A and B.To manufacture the article A,a certain

machine has to be worked for 1.5 hours and in addition a craftsman has to work for 2

hours.To manufacture the article B, the machine has to be worked for 2.5 hours and in

addition the craftsman has to work for 1.5 hours in a week the factory can avail of 80

hours of machine time and 70 hours of craftsman time.The profit on each article A is

Page 6: Linear Programming Problems-2010

Rs.50 and that on each article B is Rs.40. If all the articles produced can be sold

away,find how many of each kind should be produced to earn the maximum profit per

week.Formulate the problem as LP model.

PROBLEM 2:

An electric company is engaged in the production of two components C1 and C2 used in

T.V. sets. Each unit of C1 costs the company Rs. 25 in wages and Rs. 25 in

material,while each unit of C2 costs the company Rs. 125 in wages and Rs 75 in

material.The company sells both products on one-period credit terms, but the company’s

labour and material expenses must be paid in cash.The selling price of C1 is Rs.150 per

unit and of C2 it is Rs 350 per unit.Because of the strong monopoly of the company for

these components ,it is assumed that the company can sell at the prevailing prices as

many units as it produces. The company’s production capacity is, however, limited by

two considerations. First, at the beginning of period 1, the company has an initial balance

of Rs. 20,000(cash plus bank credit plus collections from past cedit sales). Second , the

company has available in each period 4,000 hours of machine time and 2,800 hours of

assembly time.The production of each C1 requires 6 hours of machine time and 4 hours

of assembly time,whereas the production of each C2 requires 4 hours of machine time

and 6 hours of assembly time.Formulate this problem as an LP model so as to maximize

the total profit of the company.

PROBLEM 3:

IMC manufactures a variety of computing and computer- related equipment.One such

product is a monitor for use with business computer systems and IMC currently has

plans to produce two models of the same monitor: Model A which is the basic ,low-price

monochrome monitor and Model B which is a more sophisticated and expensive colour

graphics monitor.The company is not actually involved in manufacture directly but rather

buys the various component parts which are required for the two models from outside

suppliers.The components are then assembled by IMC to produce Model A and Model B

and each unit produced is then thoroughly inspected for quality and performance.IMC

then sells the two models under its own brand name. There are, therefore, two basic

stages to the production process within the firm- the assembly of the components and the

inspection of the final product. Information about the resources required to produce the

two models has been obtained from the production department and the accounts

department.Model A requires 28 hours of labour to assemble from component parts,while

Model B requires 42 hours.After assembly each computer is then tested in the inspection

department to ensure it is working satisfactorily.Because of the technical complexity of

the product- and the firm’s desire to maintain good quality the control- the inspection

test is time-consuming,with Model A requiring 12 hours of inspection although Model B

requires only 6 hours as more care and time is taken in the assembly stage . At present the

company employs 400 people in the assembly department,each working a 7-hour day;

100 people are presently employed in the inspection department but they work an 8 hour

day.The company presently operates a 6-day working week.Current wage rates are Rs. 20

Page 7: Linear Programming Problems-2010

per hour in assembly and Rs. 15 per hour in inspection.The accounts department has

calculated that in terms of the components and parts, Model A costs Rs.355 and Model B

Rs.565 to produce.Currently the two models sel for Rs. 1,295 and Rs. 1,745

respectively.An additional aspect of the problem ,the firm faces , is that each model

requires a particular component- a microchip that forms part of the monitor’s memory.

The supplier of these chips can provide no more than 600 in any one working week.

FORMULATE a linear programming problem which allows the production manager to

determine how many units of Models A and B should be produced weekly in order to

maximize profits.

PROBLEM 4:

XYZ Electronics company produces three types of parts for automatic washing machine

.It purchases casting of the parts from a local foundry and then furnishes the part of

drilling, shaping and polishing machines.

The selling prices of part A,B and C respectively are Rs.40, Rs.50 and

Rs.70 .All parts made can be sold. Castings for part A,B and C respectively cost Rs.

25,Rs. 30 and Rs.50.

The shop possesses only one of each type of machine. Costs per hour to

run each of the three machines are Rs.100 for drilling,Rs.150 for shaping and Rs. 150 for

polishing. The capacities(parts per hour) for each part on each machine are shown in the

adjoining table:

Machine Capacity per hour

Part A Part B Part C

Drilling 25 40 25

Shaping 25 20 20

Polishing 40 30 40

The management of the shop wants to know how many parts of each

type it should produce per hour in order to maximize profit for an hour’s run. Formulate

the problem as an LP model.

PROBLEM 5:

Ex-servicemen Airport Services Company is considering the purchase of new vehicle for

the transportation between the Delhi airport and hotels in the city.There are three vehicles

under consideration: station wagons, minibuses and large buses.The purchase price would

be Rs. 1,45,000 for each station wagon, Rs. 2,50,000 for the minibus and Rs. 4,00,000 for

the large bus. The Board of Directors has authorized a maximum amount of Rs.

50,00,000 for these purchases. Because the heavy air travel, the new vehicles would be

utilized at maximum capacity regardless of the type of vehicles purchased. The expected

Page 8: Linear Programming Problems-2010

net annual profit would be Rs. 15,000 for the station wagon ,Rs. 35,000 for the minibus

and Rs. 45,000 for the large bus. The company has hired 30 new drivers for the new

vehicles. They are qualified drivers for all three types of vehicles. The maintenance

department has the capacity to handle an additional 80 wagon stations. A minibus is

equivalent of 5/3 wagon stations and each large bus is equivalent to 2 station wagons in

terms of their use of the maintenance department. Determine the optimal number of

vehicles to be purchased in order to maximize profit. FORMULATE the problem as LP

model.

PROBLEM 6:

Vitamins V and W are found in two different foods F1 and F2.One unit of food F1

contains 2 units of vitamin V and 5 units of vitamin W. One unit of food F2 contains 4

units of vitamin V and 2 units of vitamin W. One unit of food F1 and F2 cost Rs. 30 and

25 respectively. The minimum daily requirements(for a person) of vitamin V and W is

40 and 50 units respectively. Assuming that anything in excess of daily minimum daily

requirement of vitamin V and W is not harmful, find out the optimal mixture of food F1

and F2 at the minimum cost which meets the daily minimum requirement of vitamins V

and W. FORMULATE this as a Linear Programming model.

PROBLEM :7

A company is making two products A and B .T he cost of producing one unit of A and B

is Rs 60 and Rs 80 respectively .As per the agreement, the company has to supply at least

200 units of product B to its regular customers. One unit of product A requires one

machine hour whereas product B has machine hours available abundantly within the

company.Total machine hours available for product A are 400 hours. One unit each of

product A and B requires one labour hour each and total of 500 labour hours are

available. The company wants to minimize the cost of production b satisfying the given

requirements. FORMULATE the problem as a linear programming problem.

PROBLEM :8

Frontier bakery has received order from a company M/s Bodhraj Ltd., for the supply of

high protein biscuits. The order will require 1000 Kg. of biscuits mix which is made from

4 ingredients R,S T and U which cost Rs.16,Rs. 4,Rs. 6 and Rs.2per Kg. respectively.

The batch must contain a minimum of 400 Kilos of protein, 250 kilos of fat, 300 kilos of

carbohydrates and 50 Kilos of sugar. The ingredients contain the following percentage by

weight:

Ingredients Protein Fat Carbohydrates Sugar Filler

Page 9: Linear Programming Problems-2010

R

S

T

U

50% 30% 15% 5% 0%

10% 15% 50% 15% 10%

30% 5% 30% 30% 5%

0% 5% 5% 30% 60%

Only 150 kilos of S and 200 kilos of T are immediately available.

Draft a suitable LP model.

PROBLEM :9

A 24-hour supermarket has the following minimal requirements for security officers:

Table 1: STAFFING REQUIREMENTS

TIME OF DAY MINIMUM NUMBER

OF CASHIERS REQUIRED

MIDNIGHT – 4AM 7

4 AM – 8 AM 20

8 AM - NOON 14

NOON – 4PM 20

4 PM – 8 PM 10

8 PM - MIDNGHT 5

TABLE 2: SHIFT SCHEDULE

SHIFT STARTING

TIME

ENDING

TIME

1

2

3

4

5

6

MIDNIGHT

4AM

8AM

NOON

4PM

8PM

8AM

NOON

4PM

8PM

MIDNIGHT

4AM

Shift 1 follows immediately after shift 6. An officer works 8 consecutive hours, starting

at the beginning of one of the six periods. The personnel manager wants to determine

how many officers should work each shift in order to minimize the total number of

officers employed while still satisfying the staffing requirement.

Formulate the problem as a linear programming problem.

PROBLEM :10

A media specialist plans to allocate advertising expenditure in three media whose unit

costs of a message are Rs. 1500; Rs.1250 and Rs.1000 respectively. The total advertising

budget available for the year is Rs. 50000.The first medium is a monthly magazine and it

Page 10: Linear Programming Problems-2010

is desired to advertise not more than once in one issue. At least five advertisements

should appear in the second medium and the no of advertisement in the third medium

should strictly lie between 6 and 10.The effective audience for unit advertisement in the

three media is given below:

Medium: 1 2 3

Expected effective audience: 50,000 40,000 25,000

Formulate a linear programming problem to find the optimal allocation of advertisement

in three media that would maximize the total effective audience.

PROBLEM :11

A person is interested in investing Rs.5,00,000 in a mix of investments. The

investment choices and expected rates of return on each one of them are :-

Investment Projected Rate of Returns

Mutual Fund A 0.12

Mutual Fund B 0.09

Money Market Fund 0.08

Government Bonds 0.085

Share Y 0.16

Share X 0.18

The investor wants at least 35 per cent of his investment in government bonds.

Because of the higher perceived risk of the two shares, he has specified that the combined

investment in these not to exceed Rs.80,000. The investor has also specified that atleast

20 per cent of investment should be in the money market fund and that the amount of

money invested in share should not exceed the amount invested in mutual fund. His final

investment condition is that the amount invested in mutual fund A should be no more

than the amount invested in mutual fund B. the problem is to decide the amount of money

to invest in each alternative so as to obtain the highest annual total return. FORMULATE

the above as linear programming problem.

PROBLEM :12

In a chemical industry two products A and B are made involving two operations. The

production of B also results in a by-product C. the product A can be sold at a profit of Rs.

3 per unit and B at a profit of Rs. 8 per unit. The by-product C has a profit of Rs. 2 per

unit. Forecasts show that upto 5 units of C can be sold. The company gets 3 units of C for

each unit of B produced. The manufacturing times are 3 hrs per unit for A on each of the

operation one and two and 4 hrs and 5 hrs per unit for B on operations one and two

respectively. Because the product C results from producing B, no time is used in

producing C. the available times are 18 hrs and 21 hrs of operation one and two

respectively. The company desires to know that how much A and B should be produced

keeping C in mind to make the highest profit. FORMULATE LP model for this problem.

Page 11: Linear Programming Problems-2010

PROBLEM :13 A public limited company is planning its capital structure that will consist of equity

capital, 15 % debentures and term-loans. Debentures are to be repaid on face value,

interest rate is payable half yearly and annualized cost of issue of debenture is ½ %.

Interest on term-loan is 18% p.a. to be paid annually while the cost of equity is estimated

as 20%. It is decided not to have outsiders funds not more than 2 times of equity fund;

also the amount of term-loan must be at least 50% of the debenture amount.

FORMULATE a suitable LP model so as to minimize average cost of capital of the

company.

PROBLEM.14

A mutual fund has cash resources of Rs. 200 million for investment in diversified

portfolio. Table below shows the opportunities available, their estimated annual yields,

risk factors and term period details.

FORMULATE a suitable LP model to find the optimal portfolio that will maximize

returns, considering the following policy guidelines:

Investment type Annual Yield (%) Risk factors Time period (years)

Bank Deposits 9.5 0.02 6

Treasury notes 8.5 0.01 4

Corporate Deposits 12.0 0.08 3

Blue-chip Stocks 15.0 0.25 5

Speculative Stocks 32.5 0.45 3

Real Estate 35.0 0.40 10

All the funds available may be invested

Weighted average period of at least 5 years as planning horizon.

Weighted average risk factor not to exceed 0.20.

Investment in real estate and speculative stocks to be not more than 25 % of the money

invested in total.

PROBLEM.15 A company has the following independent projects available:

Project cash flows (Rs.’000)

Year A B C D E F

0 (100) - - (40) - (30)

1 (50) (60) - (60) (120) (10)

2 (10) (70) (40) 50 100 20

Page 12: Linear Programming Problems-2010

3 70 10 (80) 10 (10) 10

Cash flows extend beyond year 3 but all are cash inflows for each project

NPV

(Rs.‘000) 20 15 10 30 10 5

New capital for these projects is limited to :

Year 0 Rs. 1,20,000

Year 1 Rs. 2,00,000

Year 2 Nil

Year 3 Nil

Cash generated from these investments can be re-invested in other projects in the same

year.

EXPRESS the above problem in LP format, assuming the objective of the company is to

maximize NPV and the projects are divisible.

PROBLEM :16 A ship has three cargo loads--- Forward, after and center. The capacity limits are :

Weight (tons) Volume (in cubic Ft. )

Forward 2,000 1,00,000

Center 3,000 1,35,000

After 1,500 30,000

The following cargos are offered. The shipowner may accept all or any part of each

commodity.

Commodity Weight (tons) Volume (in cubic Ft. ) Profit per tonne ( Rs.)

A 6,000 60 150

B 4,000 50 200

C 2,000 25 125

In order to preserve the trim of the ship, the weight in each load must be proportional to

the capacity in tones. The cargo is to be distributed so as to maximize the profit.

FORMULATE the problem as LP model.

PROBLEM :17

The PQR stone company sells stones secure from any of the three adjacent quarries. The

stone sold by the company must conform to the following specifications:

Material X equal to 30%

Page 13: Linear Programming Problems-2010

Material Y equal to or less than 40%

Material Z between 30% and 40%

Stone from quarry A costs Rs. 100 per tonne and has the following properties:

Material X – 20%

Material Y – 60%

Material Z – 20%

Stone from quarry B costs Rs. 120 per tonne and has the following properties:

Material X – 40%

Material Y – 30%

Material Z – 30%

Stone from quarry C costs Rs. 150 per tonne and has the following properties:

Material X – 10%

Material Y – 40%

Material Z – 50%

From what quarries should PQR stone company secure rocks in order to minimize cost

per tonne of rocks?

PROBLEM 18

Use Simplex Method to solve the following L.P. Problem

Max.Z = 6x1 + 8x2

Subject to : 30x1 + 20x2 <300

5x1 + 10x2 < 110

x1 + x2 >0

PROBLEM 19

Use simplex method to solve the following L P problem :

Max.Z. = 6 x1 + 8 x2

Subject to Constraints :

2 x1 + 3 x2 < 16

4 x1 + 2 x2 < 16

PROBLEM 20

Use simplex method to solve the following LP Problem

Max Z = 4 x1 + 5x2+8x3

Subject to : X1 + X2 + X3 + < 100

3 x1 + 2x2 + 4x3 < 500

x1, x2, x3, >0

Page 14: Linear Programming Problems-2010

Case 1 Advertising media mix

An advertising co. wishes to plan an advertising campaign in three different media

television , radio , magazine . The purpose of advertising is to reach as many potential

customers as possible . Results of market study are as

given below

T.V. Prime

day

TV prime

time

Radio magazi

ne

Cost of an advertising unit 40000 75000 30000 15000

No of potential customers reached

per unit

400000 900000 500000 200000

No of woman customers reached

per unit

300000 400000 200000 100000

The co. does not want to spend more than Rs.8,00,000 on advertising.it is further require

that

(!) at least 2 million exposures take place among women .

(!!) advertising on television be limited to Rs. 5,00,000

(!!!) at least advertising unit be brought on prime day and two units on prime time;

(!V) the no. of advertising units on radio and magazine should each be between 5 and 10.

Formulate this problem as a lp model to maximise customer reach

Case 2 Advertising media mix

A businessman opening a new restaurant and has budgeted Rs 8,00,000 for advertising in

the coming month.

He is considering 4 types of advertising

(!) 30 seconds television commercial

(!!) 30 seconds radio commercials

(!!!) half page advertisement in news paper

(!V) full page advertisement in a weekly magazine, which will appear 4 times during the

coming month.

The owner wishes to reach families with income both over and under Rs.50000. The

amount of exposure to

families of each type and the cost of the each of the media is shown below

Media Cost of

advertisement

Exposure to families with annual

income over 50000

Exposure to families

with annual income

under50000

Television 40000 200000 300000

Radio 20000 500000 700000

News

paper

15000 300000 150000

Magazine 5000 100000 100000

To have balanced campaign, the owner has determined the following restrictions

(!) no more than 4 TV Ads.

(!!) no more than 60% of all advertisement in news paper and magazine.

(!!!) there must be 30,00,000 exposure to families with income over than 50000

(!!!) there must be 45,00,000 exposure to families with income under than 50000

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formulate the LP model to determine the no of each type of advertisement to pursue so as

to maximise the

total no of exposure

Case 3 Advertising agency Campaign

An adv. Agency is preparing an adv. Campaign for a group of agencies. These agencies

have decided that

their target customer should have following characteristics with importance as given

below

Characteristics Weightage

Age 25-40 yr. 20

Annual income Above 60000 30

Female Married 50

The agency has made a careful analysis of three media and has compiled the following

data

Data item Woman’s magazine Radio Television

Age 25-40 yr. 80 % 70 % 60 %

Annual income

above 60000

60 % 50 % 45 %

Females / married 40 % 35 % 25 %

Min. No. of adv.

Allowed

10 5 5

Cost per

advertisement

9500 25000 100000

Max. No. Of Adv.

Allowed

20 10 10

Audience size(1000) 750 1000 1500

The budget for launching the Adv. Campaign is RS 10,00,000 formulate this problem as

a IP model for the

agency to maximise the total no of effective exposure. Case 4

For XYZ Ltd the following data are relevant to its products L and P:

Per unit Product L Rs

Product p Rs

Selling Price 200.00 240.00

Costs: Direct materials 45.00 50.00

Direct wages:

Department 1 16.00 20.00

2 22.50 13.50

3 10.00 30

Variable overhead 6.50 11.50

Page 16: Linear Programming Problems-2010

Fixed overhead is budgeted at Rs 275000 per annum. Relevant data for each department are:

Number of employees

Hours per employee per week

Wage rate per hour (Rs)

Department: 1 20 40 2.00

2 15 40 2.25

3 18 40 2.50

Formulate as LP to maximize contribution

Case 5

a) A firm produces 5 different products from a single raw material. Raw materials

is available in abundance at Rs. 6 per Kg.The labour rate is Rs. 8 per hour for all products. The plant capacity is 21000 labour hours for the budget period. Production facilities can produce all the products. The factory overhead rate is Rs. 8 per hour, comprising Rs. 5.60 per hour as fixed overheads and Rs. 2.40 per hour as variable overheads. The selling commission is 10 percent of the product price. Given the following information, formulate LPP to maximize the Company’s profits.

Product Market demands(units)

Selling price per units(Rs)

Labour hours required per unit

Raw material required per unit (in gms)

A 4000 32.00 1.00 700

B 3600 30.00 0.80 500

C 4500 48.00 1.50 1500

D 6000 36.00 1.10 1300

E 5000 44.00 1.40 1500

B) Assume, in above situation, 3500 hours of overtime working is possible. It will result in additional fixed overheads of Rs 20000 a doubling of labour rates and a 50 percent increase in variable overheads. Formulate LPP to decide about the overtime working. Case 6

A manufacturer of biscuits is considering four types of gift packs containing

three types of biscuits. Orange cream (OC), Chocolate cream (CC) and

Wafers (W). A market research study conducted recently to assess the

preference of the consumers shows the following types of assortments to be

in good demand :

Page 17: Linear Programming Problems-2010

Assortments Contents Selling price per Kg (Rs)

A Not less than 40% of OC 20

Not more than 20% of CC

B Not less than 20% of OC 25

Not more than 40% of CC

Any quantity of W

C Not less than 50% of OC 22

Not more than 10% of CC

Any quantity of W

D No restrictions 12

For the basics, the manufacturing capacity and costs are given below :

Type of biscuit Plant capacity (kg/day) Manufacturing cost

(Rs/kg)

OC 200 8

CC 200 9

W 150 7

Formulate this problem as an LP model to find the production

schedule which maximizes the profit, assuming that there are no market

restrictions.