The maximum value of the objective function $z = 2x + 3y$ of an L.P.P. subjected to the constraints $x-y≤1,x + y ≤3,x,y≥0$, is
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 9
Given:
Objective function: $z = 2x + 3y$
Subject to constraints:
- $x - y \leq 1$
- $x + y \leq 3$
- $x \geq 0,\ y \geq 0$
Step 1: Find corner points of feasible region
Intersection of $x - y = 1$ and $x + y = 3$:
Solving:
- Add: $2x = 4 \Rightarrow x = 2$
- Substitute: $2 + y = 3 \Rightarrow y = 1$
⇒ Point A: $(2, 1)$
Intersection with axes:
- $x - y = 1$ and $y = 0$ ⇒ $x = 1$ ⇒ Point B: $(1, 0)$
- $x + y = 3$ and $x = 0$ ⇒ $y = 3$ ⇒ Point C: $(0, 3)$
Also include origin $(0, 0)$
Step 2: Evaluate $z = 2x + 3y$ at all corner points
- At $(0, 0)$: $z = 0$
- At $(1, 0)$: $z = 2$
- At $(2, 1)$: $z = 2(2) + 3(1) = 4 + 3 = 7$
- At $(0, 3)$: $z = 9$