Linear Programming — Class 12 Maths Solution

ncert exercise SA NCERT,Ex.12.1,Q.3,page.513
Question

Maximize $Z = 5x + 3y$ subject to$3x + 5y \le 15,5x + 2y \le 10,x \ge 0,y0.$

Step-by-step Solution

.: The system of constraints is :
$3x + 5y \le 15$ ...(1)

$5x + 2y \le 10$ ...(2)

and $x \ge 0,y \ge 0$ ...(3)

Let ${l_1}:3x + 5y = 15$

${l_2}:5x + 2y = 10$

The shaded region in the adjoining figure is

the feasible region determined by the system of constraints (1) to (3).

figure

It is observed that the feasible region OCEB is bounded.

Thus, we use Corner Point Method to determine the maximum value of Z.

We have :$Z = 5x + 3y$ ...(4)

The co-ordinates of $O,C,E$ and B are (0, 0), (2, 0), $\left( {\cfrac{{20}}{{19}},\cfrac{{45}}{{19}}} \right)$

(on solving$3x + 5y = 15,5x + 2y = 10$ ) and (0, 3) respectively.

figure

Hence,${Z_{\max }} = \cfrac{{235}}{{19}}$ at $\left( {\cfrac{{20}}{{19}},\cfrac{{45}}{{19}}} \right)$

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