Maximum value of $z=5 x+4 y$ subject to the constraints $x-y \leq 0, x+y \leq 4, x \geq 0, y \geq 0$ occurs at the point (a, b), then 4a + 5b = ________.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) - 18
| corner points | $Z(x,y)=5x+4y$ |
| $(0,4)$ | $Z(0,4)=16$ |
| $(2,2)$ | $Z(2,2)=18$ |
| $(0,0)$ | $Z(0,0)=0$ |
$(a,b)=(2,2)$
so $4a+5b=18$