Final answer:
The marginal revenue product of labor in a purely competitive market is calculated by multiplying the marginal product by the market price of the product.
Step-by-step explanation:
For a firm selling its product in a purely competitive market, the marginal revenue product of labor can be found by multiplying the marginal product by the product price. This is because in a perfectly competitive market, firms are price takers, meaning they sell their product at the market price. Therefore, each additional unit of output produced by an extra unit of labor (the marginal product) will sell for the market price. Hence, the marginal revenue product (MRP) is the increase in total revenue from hiring one more unit of labor and is equal to the marginal product (MP) times the market price.