Final answer:
In a purely competitive market, marginal revenue is equal to the price.
Step-by-step explanation:
In a purely competitive market, the marginal revenue is equal to the price.
For a perfectly competitive firm, marginal revenue is constant because it is determined by the market price. The firm takes the market price as given and increases its quantity of output. As a result, total revenue steadily increases at a constant rate determined by the market price.