Explain solution RD Sharma class 12 Chapter 29 Linear Programming exercise 29.4 question 23
Answer:
Minimum cost = Rs.92 when 100kg of type I fertilizer and 80 kg of Type II fertilizer is supplied.
Hint:
Form Linear Equation and solve graphically.
Given:
A gardener supply fertilizer of type I which consists of 10% of nitrogen and 6% phosphoric acid and Type II fertilizer which consist of 5% nitrogen and 10% of phosphoric acid. After testing the soil conditions, he finds that he needs at least 14 kg of nitrogen and 14kg of phosphoric acid for two crop of the type I fertilizer cost 60P/Kg and types II fertilizer 40P/Kg
Solution:
Let x kg of Type I fertilizer and y kg of Type II fertilizers are supplied.
The quantity of fertilizers cannot be negative.
So,
A gardener has a supply of fertilizer of type I which consists of 10% nitrogen and type II consists of 5% nitrogen, and he needs at least 14kg for his crop.
So,
Or
A gardener has a supply of fertilizer of type I which consists of 6% phosphoric acid and type II consists of 10% phosphoric acid, and he needs at least 14 kg of phosphoric acid for his crop.
Sp,
Or
Therefore, A/Q, constraint is,
If the type I fertilizer costs 60 paise per kg and Type II fertilizer costs 40 paise per kg. Therefore, the cost of x kg of Type 1 fertilizer and y kg of Type II fertilizer is Rs.0.60x and Rs.0.40y respectively.
Total cost=Z(let)=0.6x + 0.4y is to be minimized.
Thus the mathematical formulation of the given LPP ism,
Min Z=0.6 + 0.4y
Subject to the constraints,
Region represented by : the line passes through , B(0,140). The region which does not contains origin represents solutions of the in equation as (0,0) doesn’t satisfy the in equation
Region represented by : the line passes through C(140,0) and D(0,280). The region which does not contains origin represents solutions of the in equation as (0,0) doesn’t satisfy the in equation
The region : represents the first quadrant.
The corner points are D(0,280),E(100,80), A(700/3,0)
The values of Z at these points are as follows:
Corner Points |
|
O |
0 |
D |
112 |
E |
92 |
F |
140 |
The minimum value of Z is Rs.92 which is attained at E(100,80)
Thus, the minimum cost is Rs.92 obtained when 100kg of Type I fertilizer and 80 kg of Type II fertilizer is supplied.