Final answer:
The profit-maximizing quantity for Doggies Paradise Inc. is 4 units.
Step-by-step explanation:
The profit-maximizing quantity for Doggies Paradise Inc. can be determined by comparing total revenue and total cost at each output level. By calculating total revenue and total cost for each output level (one to five units) using the given information, we can see that the highest profit occurs at the output level of 4 units, where total revenue is $288 and total cost is $228.
To graphically represent this, we can sketch the total revenue and total cost curves on one diagram, and the marginal revenue and marginal cost curves on another diagram. The profit-maximizing quantity is the level of output where the marginal revenue equals the marginal cost, which in this case is 4 units.