Linear Programming — Class 12 Maths Solution

ncert exercise SA NCERT,Ex.12.2,Q.2,page.519
Question

One kind of cake requires 200 g of flour and 25 g of fat and another kind of cake requires 100 g of flour and 50 g of fat. Find the maximum number of cakes which can be made from 5 kg of flour and 1 kg of fat assuming that there is no shortage of the other ingredients used in making the cakes.

Step-by-step Solution

. : Let x be the number of cakes of first kind and y be the number of cakes of second kind.

Clearly, $x \ge 0,y \ge 0$. We make the following table from the given data :

figure

Since the maximum number of cakes can be made from 5 kg of flour and 1 kg of fat,

we have the constraints
$200x + 100y \le 5000$

$25x + 50y \le 1000$

Total number of cakes to be made is $Z = x + y$

Hence, the mathematical formulation of the problem is :

Maximize $Z = x + y$ ...(1)

subject to the constraints
$2x + y \le 50$ ... (2)

$x + 2y \le 40$ ... (3)

$x,y \ge 0$ ... (4)

${l_1}:2x + y = 50;$ ${l_2}:x + 2y = 40$

Let us graph the inequalities (2) to (4).

figure

The feasible region determined by the system is shown in the graph.

Here, we observe that the feasible region is bounded.

Let us evaluate Z at the comer points A(25, 0), E(20, 10) and B(0, 20).

Hence, maximum number of cakes is 30 when 20 cakes of one

kind and 10 cakes of another kind can be made with given ingredients.

NCERT & Exemplar solution for CBSE Class 12 Mathematics, Linear Programming. Curated by Sachin Sharma. Free for all students.