The demand function for a certain product is represented by the equation: \( p=40+5x-2x^{2} \), where \( x \) is the number of units demanded and \( p \) is the price per unit, then the marginal revenue (in Rs.) when 3 units are sold, is
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Rs. 16
The revenue is price times quantity:
\( \displaystyle R(x)=p\cdot x=40x+5x^{2}-2x^{3} \)
The marginal revenue is its derivative:
\( \displaystyle MR=\frac{dR}{dx}=40+10x-6x^{2} \)
At x = 3:
\( \displaystyle MR=40+30-54=16 \)
So the marginal revenue is Rs. 16.
CBSE Applied Mathematics (Class XII):
Marginal Cost and Marginal Revenue
