The demand for a product is $x = 100 - 2p$, where $p$ is the price in rupees. What is the marginal revenue when 20 units are sold?

Explanation

1. 01

   Solve for the price: $p = 50 - \frac{x}{2}$, so $R(x) = 50x - \frac{x^{2}}{2}$.

2. 02

   $MR = 50 - x$; at $x = 20$, 30 rupees.