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

Question:

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

$R(x)=13 x^{2}+26 x+15$

Find the marginal revenue when x = 7.

Solution:

Marginal revenue is the rate of change of total revenue with respect to the number of units sold.

$\therefore$ Marginal Revenue $(\mathrm{MR})=\frac{d R}{d x}=13(2 x)+26=26 x+26$

When x = 7,

$M R=26(7)+26=182+26=208$

Hence, the required marginal revenue is Rs 208.