
Step 1: {Identify the corner points of the feasible region}
From the graph, the vertices of the feasible region are: \[ A(0, 50), \, B(20, 30), \, C(30, 0). \]
Step 2: {Substitute corner points into \( Z = 4x + y \)}
Evaluate \( Z \) at each vertex: \[ Z_A = 4(0) + 50 = 50,\] \[\quad Z_B = 4(20) + 30 = 110,\]
\(\quad Z_C = 4(30) + 0 = 120.\)
Step 3: {Find the maximum value}
The maximum value of \( Z \) occurs at \( C(30, 0) \), where \( Z = 120 \).
Step 4: {Verify the options}
The maximum value is \( 120 \), which corresponds to option (C).
A carpenter needs to make a wooden cuboidal box, closed from all sides, which has a square base and fixed volume. Since he is short of the paint required to paint the box on completion, he wants the surface area to be minimum.
On the basis of the above information, answer the following questions :
Find \( \frac{dS}{dx} \).
