Method of Solving LPP

IMPORTANT

Method of Solving LPP: Overview

This topic covers concepts, such as, Solutions of a Linear Programming Problem,Feasible Solutions to a Linear Programming Problem,Optimal Solutions of a Linear Programming Problem etc.

Important Questions on Method of Solving LPP

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What are conflicting constraints. Show that the LPP in which the objective function z=6x+4y is to be minimized subject to the constraints 3x+2y18 and 2x+y16 x0, y0 has infinitely many optimal solutions.

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What are conflicting constraints. 

Show that the LPP of which two constraints are 3x-5y7 and 10y9+6x has no optimal solution.

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What are conflicting constraints. Show that if each of the infinitely many optimal solutions of an LPP with objective function z=ax+by, lies on the line 15 x+25 y=32 with 5a=3b.

MEDIUM
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What are conflicting constraints. Find optimal solution of the following LPP, Maximize z=2x+3y subject to 5x+4y20, where x0, y0.

MEDIUM
IMPORTANT

What are conflicting constraints. 

Show that the optimal solution of the following LPP

Maximize z=5x+3y

Subject to, x+2y16,

0y3,

x0

lies on the straight line 2x+5y=32.

HARD
IMPORTANT

State the Convex polygon theorem.

Find convex region from the following figures.

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A gardener has a supply of fertilizers of the type one which consist of 10% nitrogen and 6% phosphoric acid, and of the type two which consist of 5% nitrogen and 10% phosphoric acid. After testing the soil condition, he finds that he needs at least 14 g of nitrogen and 14 g of phosphoric acid for his crop. If the type one fertilizer costs 60 paise per g and the type two fertilizer costs 40 paise per g, determine how many grams of each type of fertilizer should be used so that the nutrient requirement are met at a minimum cost. What is the minimum cost?

HARD
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State the Convex polygon theorem.

Find convex region from the following figures.

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An oil company has two depots, a and b, with capacities of 7000 ml and 4000 ml respectively. The company is to supply oil to three pumps, d,e,f, whose requirements are 4500 ml, 3000 ml, and 3500 ml respectively. The distances (in m) between the depots and the petrol pumps are given in the following table:

  Distance in m 

From 

To

a b
d 7 3
e 6 4
f 3 2

Assuming that the transportation cost per m is 1 paise per ml, how should the delivery be scheduled in order that the transportation cost is minimum?

EASY
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State the Convex polygon theorem.

Find convex region from the following figures.

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The corner points of the feasible region determined by the following system of linear inequalities:
2x+y10,x+3y15,x,y0 are 0,0,5,0,3,4 and 0,5
Let Z=sx+ty, where s,t>0.
Condition on s and t so that the maximum of Z occurs at both 3,4 and 0,5 is

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Solve z=2x+3y, subject to x+y62x+y16x0y0 graphically. Check whether it has feasible or infeasible solution.

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Solve z=3x+2y, subject to x+y52x+y20x0y0 graphically. Check whether it has feasible or infeasible solution.

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Solve z=2x+2y, subject to x+y5x+2y14x0y0 graphically. Check whether it has feasible or infeasible solution.

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Solve z=x+2y, subject to x+y53x+y21x0y0 graphically. Check whether it has feasible or infeasible solution.

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Solve z=4x+3y, subject to x+y62x+y20x0y0 graphically. Check whether it has feasible or infeasible solution.

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Check if z=4x+3y, subject to x+y62x+y20x0y0 has feasible or infeasible solution graphically.

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A company makes two products (X and Y) using two machines (A and B). Each unit of X that is produced requires 50 minutes processing time on machine A and 30 minutes processing time on machine B. Each unit of Y that is produced requires 24 minutes processing time on machine A and 33 minutes processing time on machine B. At the start of the current week there are 30 units of X and 90 units of Y in stock. Available processing time on machine A is forecast to be 40 hours and on machine B is forecast to be 35 hours. The demand for X in the current week is forecast to be 75 units and for Y is forecast to be 95 units. Company policy is to maximize the combined sum of the units of X and the units of Y in stock at the end of the week. Formulate the problem of deciding how much of each product to make in the current week as a linear program. Solve this linear program graphically

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A small firm manufactures necklace and bracelets. The total number of necklace and bracelet that it can handle per day is at most 24. It takes 1hour to make a bracelet and half an hour to make a necklace. The maximum number of hours available per day is 16. If the profit on a necklace is 100 and that on a bracelet is 300, how many of each should be produced daily to maximize the profit? It is being given that at least one of each must be produced.

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Mr.Dass wants to invest 12000 in public provident fund (PPF) and in national bonds. He has to invest at least 1000 in PPF and at least 2000 in bonds. If the rate of interest on PPF is 12% per annum and that on bonds is 15% per annum, how should he invest the money to earn maximum annual income? Also find the maximum annual income.

MEDIUM
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For the following Linear Programming problems with given constraints 4x+6y60, 2x+y20 and x0, y0. The maximum value of z=2x+3y is

MEDIUM
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For the following linear Programming problems, subject to the constraints x+y4 and x0 , y0. Find the maximum value of Z=3x+4y

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For the following linear Programming problem, subject to the constraints x+2y83x+2y12 and x0 , y0. Find the minimum value of Z=-3x+4y.