Final answer:
The marginal revenue product of the third worker at the campus coffee shop is $70 per hour, which is calculated by the increase in output attributable to the hiring of that worker.
Step-by-step explanation:
The marginal revenue product (MRP) of labor is the increase in revenue a firm experiences from hiring an additional worker. In the scenario provided, hiring a third worker increased the coffee shop's output from $175 to $245 per hour. Therefore, the marginal revenue product of the third worker can be computed as the difference in output divided by the number of additional workers, which in this case is just one.
The marginal revenue product (MRP) of labor is the additional revenue generated by adding one more unit of labor. In this case, hiring a third worker increases output from $175 per hour to $245 per hour. Therefore, the MRP of the third worker is $245 - $175 = $70 per hour.
To calculate the MRP, subtract the total output before the worker was hired ($175) from the total output after they were hired ($245).
Marginal Revenue Product = $245/hr - $175/hr = $70/hr
Thus, the third worker's marginal product is worth more than $8 per hour, as this is the additional revenue they bring to the firm per hour.