In Fig. 12.11, the feasible region (shaded) for a LPP is shown. Determine the maximum and minimum value of \mathbf{Z}=\mathbf{x}+2 \mathbf{y}
In Fig. 12.11, the feasible region (shaded) for a LPP is shown. Determine the maximum and minimum value of \mathbf{Z}=\mathbf{x}+2 \mathbf{y}

NCERT Exemplar Solutions Class 12 Mathematics Chapter 12 - 11

Solution:

It is seen from the given figure, that the corner points are as follows:

\mathrm{R}(7 / 2,3 / 4), \mathrm{Q}(3 / 2,15 / 4), \mathrm{P}(3 / 13,24 / 13) and \mathrm{S}(18 / 7,2 / 7)

On evaluating the value of \mathrm{Z} for the feasible region RQPS.

    \[\begin{tabular}{|l|l|} \hline Corner points & Value of $\mathrm{Z}=\mathrm{x}+2 \mathrm{y}$ \\ \hline $\mathrm{R}(7 / 2,3 / 4)$ & $\mathrm{Z}=7 / 2+2(3 / 4)=5$ \\ \hline $\mathrm{Q}(3 / 2,15 / 4)$ & $\mathrm{Z}=3 / 2+2(15 / 4)=9$ \\ \hline $\mathrm{P}(3 / 13,24 / 13)$ & $\mathrm{Z}=3 / 13+2(24 / 13)=51 / 13$ \\ \hline $\mathrm{S}(18 / 7,2 / 7)$ & $\mathrm{Z}=18 / 7+2(2 / 7)=22 / 7$ \\ \hline \end{tabular}\]

It is seen from the above table that the minimum value of Z is 22 / 7 and maximum value of Z is 9.

Thus, the maximum value of \mathrm{Z} is 9 at (3 / 2,15 / 4) and the minimum value of \mathrm{Z} is 22 / 7 at (18 / 7,2 / 7).