The total revenue received from the sale of x units of a product is given by

$R(x)=36x+3x^2+5.$

Then the difference between Marginal revenue and Average revenue when x= 5 is :

14

The correct answer is Option (2) → 14

The total revenue function,

$R(x)=36x+3x^2+5$

and,

Average Revenue (AR),

$AR=\frac{R(x)}{x}=\frac{36x+3x^2+5}{x}$

$AR=36+3x+\frac{5}{x}$

$⇒AR(5)=36+3×5+\frac{5}{5}=52$

Now,

Marginal Revenue, $MR(x)=\frac{d}{dx}(36x+3x^2+5)$

$=36+6x$

$⇒MR(5)=36+6×5=66$

$∴MR-AR=66-52=14$