Question:medium

Maximize \( Z = 2x+3y \), subject to the constraints:
\( x+y \le 2 \)
\( 2x+y \le 3 \)
\( x,y \ge 0 \)

Show Hint

For 2-variable LPPs, the graphical method is fastest. Quickly sketch the lines, shade the feasible region, and identify the corner points. The optimal solution (max or min) is guaranteed to be at one of these corners. Always check that your intersection points satisfy all constraints.
Updated On: Feb 10, 2026
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The Correct Option is B

Solution and Explanation

Step 1: Understanding the Problem:
This is a linear programming problem (LPP) aimed at maximizing a linear objective function \(Z\) subject to linear inequality constraints, which define a feasible region. The maximum of \(Z\) is located at a vertex of the feasible region.

Step 2: Method:
1. Graph the inequalities to find the feasible region. 2. Identify the vertices of this region. 3. Calculate the objective function \(Z = 2x+3y\) at each vertex. 4. The largest value of \(Z\) is the maximum value.

Step 3: Detailed Solution:
The constraints are: 1. \( x \ge 0, y \ge 0 \) (First quadrant) 2. \( x+y \le 2 \) (Below the line \(x+y=2\)) 3. \( 2x+y \le 3 \) (Below the line \(2x+y=3\)) Vertices of the feasible region are found as follows:
Vertex 1 (Origin): Intersection of \(x=0\) and \(y=0\), which is \((0,0)\).
Vertex 2 (x-intercept): Intersection of \(y=0\) and \(2x+y=3\). This gives \(x=1.5\), so the point is \((1.5, 0)\). (Check: \(1.5+0 \le 2\) is true).
Vertex 3 (y-intercept): Intersection of \(x=0\) and \(x+y=2\), resulting in \(y=2\). The point is \((0,2)\). (Check: \(2(0)+2 \le 3\) is true).
Vertex 4 (Intersection of lines): Intersection of \(x+y=2\) and \(2x+y=3\). Subtracting the equations: \((2x+y) - (x+y) = 3-2 \implies x=1\). Substituting \(x=1\) into \(x+y=2\): \(y=1\). The point is \((1,1)\). The vertices are (0,0), (1.5, 0), (0,2), and (1,1). Evaluate \(Z=2x+3y\) at each vertex:
At (0,0): \( Z = 2(0) + 3(0) = 0 \)
At (1.5, 0): \( Z = 2(1.5) + 3(0) = 3 \)
At (0,2): \( Z = 2(0) + 3(2) = 6 \)
At (1,1): \( Z = 2(1) + 3(1) = 5 \) The values of Z are 0, 3, 5, and 6. The maximum value is 6.
Step 4: Answer:
The maximum value of Z is 6, at (0,2).
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