A firm hires labor in a perfectly competitive labor market. Its current profit-maximizing hourly output is 100 units, which the firm sells at a price of $5 per unit. The Marginal Physical product (MPP) of the last unit of labor employed is 5 units per hour. The firm pays each worker an hourly wage of $15. a)What Marginal Revenue (MR) does the firm earn from sale of the output produced by the last worker employed? b)Does this firm sell its output in a perfectly competitive market?

Based on the information given we were told that the Marginal Physical product of the last unit of labor was 5 units per hour in which the firm pays each worker an hourly wage of $15. Now let calculate the Marginal Revenue using this formula

Marginal Revenue = Employees hourly wages/Marginal Physical product unit of labor

Where,

Employees hourly wages=$15

Marginal Physical product unit of labor =5 units per hour

Let plug in the formula

Marginal Revenue =$15/5

Marginal Revenue =$3

B. No reason been that the current profit-maximizing hourly output was 100 units in which we were told that the firm sells at a price of $5 per unit. While the Marginal Revenue gotten in (A) above was $3 which is lesser or lower than $5 per unit which simply means that the firm does NOT sell its output in a well perfectly competitive market .