Answer
The average revenue is 10 dollars and 50 units were sold.
Work Step by Step
In a competitive market, a firm's marginal revenue will be equal to both its average revenue and price. Because we know that this firm's marginal revenue is 10 dollars, we also know that its average revenue is also 10 dollars.
To calculate the number of units sold, we divide the firm's total revenue of 500 dollars by the price of each unit — 10 dollars — and we get 50 units.
