Final answer:
Marginal revenue is the change in total revenue resulting from selling one more unit. It is calculated by dividing the change in total revenue by the change in quantity. Marginal revenue helps firms determine profit.
Step-by-step explanation:
The change in total revenue resulting from selling one more unit is called marginal revenue. Marginal revenue is calculated as the change in total revenue divided by the change in quantity. It helps a firm determine whether its marginal unit is adding to profit.