Final answer:
The exact square footage for storing paint is not given, but examples of converting painting jobs into a linear equation and the calculation of the marginal product of the third painter were provided.
Step-by-step explanation:
Unfortunately, the question about how many square feet are there for storing paint on a 3-square-foot shelf is incomplete as it does not provide enough information or a table to reference. However, I can help with the other mathematical problems presented.
To complete a painting job as a linear equation
To express the time it takes to complete a painting job as a linear equation, consider the equation T = 4 + 1/1000S, where T represents the total time in hours and S represents the square footage to be painted.
Marginal Product of the Third Painter
The marginal product of labor is the increase in output that results from an additional unit of labor. In this case, two painters paint 200 square feet in an hour, and three painters can paint 275 square feet in an hour. Thus, the marginal product of the third painter is the difference in square feet per hour painted by three painters compared to two, which is 275 - 200 = 75 square feet per hour.