Question

 

A brick manufacturer has two depots, A and B, with stocks of 30,000 and 20,000 bricks respectively. He receives orders from three builders PQand R for 15,000, 20,000 and 15,000 bricks respectively. The cost in Rs transporting 1000 bricks to the builders from the depots are given below:  

              From

To

P

Q

R

A

40

20

30

B

20

60

40

How should the manufacturer fulfill the orders so as to keep the cost of transportation minimum? 

Solution

Correct option is

x = 0, y = 0, Z = 1200 & Thus, the manufacturer should supply 0, 20 and 10 thousand bricks to builders PQ and R from depot A and 15, 0 and 5 thousand bricks to builders PQ and R from depot B respectively. In this case the minimum transportation cost will be Rs 1200

 

Let the depot A transport x thousand bricks to builder P and y thousand bricks to builder Q. Then, the above LPP can be stated mathematically as follows:   

     Minimize Z = 30x – 30y + 1800   

Subject to   

     x + y ≤ 30

           x ≤ 15

           y ≤ 20   

     x + y ≥ 15   

and,  x ≥ 0, y ≥ 0   

To solve this LPP graphically, we first convert inequations into equations and then draw the corresponding lines. The feasible region of the LPP is shaded in fig. The coordinates of the corner points of the feasible regionA2PQB3B2 are A2(15, 0), P(15, 15), Q (10, 20), B(0, 20) and B2 (0, 15). These points have been obtained by solving the corresponding intersecting lines simultaneously. 

The values of the objective function at the corner points of the feasible region are given in the following table. 

                                                               

 

 

Point (xy)

Value of the objective function

         Z = 30x – 30y + 1800    

A (15, 0)

P (15, 15)

Q (10, 20)

B3 (0, 20)

B2 (0, 15)

Z = 30 × 15 – 30 × 0 + 1800 = 2250

Z = 30 × 15 – 30 × 15 + 1800 = 1800

Z = 30 × 10 – 30 × 20 + 1800 = 1500

Z = 30 × 0 – 30 × 20 + 1800 = 1200

Z = 30 × 0 – 30 × 15 + 1800 = 1350    

Clearly, Z is minimum at x = 0, y = 20 and the minimum value of Z is 1200.    

Thus, the manufacturer should supply 0, 20 and 10 thousand bricks to builders PQ and R from depot A and 15, 0 and 5 thousand bricks to builders PQ and R from depot B respectively. In this case the minimum transportation cost will be Rs 1200.   

 

SIMILAR QUESTIONS

Q1

A dietician wishes to mix two types of food in such a way that the vitamin contents of the mixture contain at least 8 units of vitamin A and 10 units of vitamin C. Food ‘I’ contains 2 units/kg of vitamin A and 1 unit/kg of vitamin C while food ‘II’ contains 1 unit/kg of vitamin A and 2 units/kg of vitamin C. It costs Rs 5.00 per kg to purchase food ‘I’ and Rs 7.00 per kg to produce food ‘II’. Determine the minimum cost to such a mixture. formulate the above as a LPP and solve it. 

Q2

Every gram of wheat provides 0.1 gm of proteins and 0.25 gm of carbohydrates. The corresponding values of rice are 0.05 gm and 0.5 gm respectively. Wheat costs Rs. 4 per kg and rice Rs. 6. The minimum daily requirements of proteins and carbohydrates for an average child are 50 gms and 200 gms respectively. In what quantities should wheat and rice be mixed in the daily diet to provide minimum daily requirements of proteins and carbohydrates at minimum cost.    

Q3

A manufacturer produces nuts and bolts for industrial machinery. It takes 1 hour or work on machine A and 3 hours on machine B to produce a package of nuts while it takes 3 hours on machine A and 1 hour on machine B to produce a package of bolts. He earns a profit of Rs 2.50 per package of nuts and Re 1.00 per package of bolts. How many packages or each should he produce each day so as to maximize hit profit, if he operates his machines for at most 12 hours a day? Formulate this mathematically and then solve it.  

Q4

An oil company requires 12,000, 20,000 and 15,000 barrels of high-grade, medium grade and low grade oil, respectively. Refinery A produces 100, 300 and 200 barrels per day of high-grade, medium-grade and low-grade oil, respectively, while refinery B produces 200, 400 and 100 barrels per day of high-grade, medium-grade and low-grade oil, respectively. If refinery A costs Rs 400 per day and refinery B  costs Rs 300 per day to operate, how many days should each be run to minimize costs while satisfying requirements.

Q5

A company produces soft drinks that has a contract which requires that a minimum of 80 units of the chemical A and 60 units of the chemical B to go into each bottle of the drink. The chemicals are available in a prepared mix from two different suppliers. Supplier S has a mix of 4 units of A and 2 units of B that costs Rs 10, the supplier T has a mix of 1 unit of A and 1 unit of B that costs Rs 4. How many mixes from S and T should the company purchase to honour contract requirement and yet minimize cost?

Q6

A dealer wishes to purchase a number of fans and sewing machines. He has only Rs 5760.00 to invest and has space for at most 20 items. A fan costs him Rs 360.00 and a sewing machine Rs 240.00. His expectation is that he can sell a fan at a profit of Rs 22.00 and a sewing machine at a profit of Rs 18.00. Assuming that he can sell all the items that he can buy, how should he invest his money in order to maximize his profit? Translate this problem mathematically and then solve it. 

Q7

A farm is engaged in breeding pigs. The pigs are fed on various products grown on the farm. In view of the need to ensure certain nutrient constituents (call them XY and Z). it is necessary to buy two additional products, say A and B. One unit of product A contains 36 units of X, 3 units of Y, and 20 units of Z. One unit of product B contains 6 units of X, 12 units of Y and 10 units of Z. The minimum requirement of XY and Z is 108 units, 36 units and 100 units respectively. Product A costs Rs 20 per unit and product B costs Rs 40 per unit. Formulate the above as a linear programming problem to minimize the total cost, and solve the problem by using graphical method. 

Q8

A toy manufacturer produces two types of dolls; a basic version doll Aand a deluxe version doll B. Each doll of type B takes twice as long to produce as one doll of type A. The company have time to make a maximum of 2000 dolls of type A per day, the supply of plastic is sufficient to produce 1500 dolls per day and each type requires equal amount of it. The deluxe version, i.e. type B requires a fancy dress of which there are only 600 per day available. If the company makes a profit of Rs 3 and Rs 5 per doll, respectively, on doll A and B; how many of each should be produced per day in order to maximize profit? Solve it by graphicl method.

Q9

 

There is a factory located at each of the two places P and Q. From these locations, a certain commodity is delivered to each of these depots situated at AB and C. The weekly requirements of the depots are respectively 5, 5 and 4 units of the commodity while the production capacity of the factories at P and Q are respectively 8 and 6 units. The cost of transportation per unit is given below:  

                   To

From

Cost (in Rs)

A

B

C

P

16

10

15

Q

10

12

10

         

How many units should be transported from each factory to each depot in order that the transportation cost in minimum. Formulate the above LPP mathematically and then solve it.