Answer:
3 cases
Step-by-step explanation:
Marginal product refers to change in the total output when an additional input is employed. For example, output is 5 units when 2 laborers are employed. When another unit of input i.e 3rd laborer is employed, the output rises to 9 units. In this case marginal product of the 3rd unit of labor would be 9 - 5 i.e 4 units.
In the given case, before Atul is hired, the production was 4 cases per week. After his being hired, it rose to 7 cases per week. Thus Atul's marginal product in the given case would be 7 - 4 i.e 3 cases.