Question
Solve the following L.P.P. using graphical method:
Minimize, $z=8 x+10 y$
Subject to $2 x+y \geq 7,2 x+3 y \geq 15, y \geq 2, x \geq 0$

Answer

To draw line
$x$$y$The line passes through $(x, y)$
signOrigin lies on
$L_1:$ $2 x+y=7$
07$A (0,7)$
3.50$B (3.5 .0)$
$\geq$Non origin side of $L _1$
$L _2:$ $2 x+3 y=15$
05$C (0,5)$
7.50$B (7.5,0)$
$\geq$Non origin side of $L_2$
$L _3: $ $y=2$$L _3$ is parallel to x-axis$z$Non origin side of $L_3$

Solving equations of $L_1$ and $L_2$
$2 x+y=7$
$2 x+3 y=15$
____________
$y=4, \quad x=1.5$
$\therefore P (1.5,4)$
Solving equations of $L _2, L _3$
$Q=(4.5 ; 2)$
Image
The shaded feasible region is unbounded feasible region in the graph with vertices at $A (0,7), P (1.5,4)$ and $Q (4.5,2)$

$(x, y)$ VerticesValue of $Z =8 x+10 y$
$A (0,7)$70
$P (1.5,4)$$12+40=52$
$Q (4.5,2)$$36+20=56$

From the above table, minimum value of $Z$ is 52 at $x=1.5, y=4$.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free