Target Exam

CUET

Subject

-- Applied Mathematics - Section B2

Chapter

Calculus

Question:

The cost of manufacturing x units of a commodity is $27 + 15x+3x^2$. Find the output where AC = MC.

Options:

$x=1$

$x=2$

$x=3$

$x=4$

Correct Answer:

$x=3$

Explanation:

The correct answer is Option (3) → $x=3$

$C(x)=27 + 15x+3x^2$

$∴AC=\frac{C}{x}=\frac{27}{x}+15+3x$

$MC=\frac{dC}{dx}=\frac{d}{dx}(27 + 15x+3x^2)=15+6x$

$∴MC=AC⇒15+6x=\frac{27}{x}+15+3x⇒3x=\frac{27}{x}$

$⇒x^2=9⇒x=3$