If a monopolist can sell 20 units at price of $200 per unit and 30 units at a price of $180 per unit, its marginal revenue at an output of 30 is
A) $-200.
B) $800.
C) $1400.
D) $1800.

Question

Quizplus · Accepted Answer

Marginal revenue is the change in total revenue divided by the change in quantity sold. In this case, the change in total revenue is $1800 - $4000 = -$2200, and the change in quantity sold is 30 - 20 = 10. Therefore, the marginal revenue is -$2200 / 10 = -$220.

If a Monopolist Can Sell 20 Units at Price of $200