According to the question:
and the constraints
.
Plotting all the constrain equations we see that the shaded area OABC is the feasible region determined by the constraints.
The feasible region is bounded with four corner points
.
So, the maximum value can occur at any corner.
On evaluating the value of Z, we get
From the above table it’s seen that the maximum value of Z is
.
Therefore, the maximum value of the function Z is
at
.