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

R(x) = 3x² + 36x + 5. The marginal revenue, when x = 15 is

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

Then,

So, when x = 15 then,

MR = 6(15) + 36 = 126

Therefore, the marginal revenue when x = 15 is Rs. 126.