A natural spring flows exclusively on Ben's property. Residents of nearby Dry Gulch believe that minerals in the stream give the water special medicinal value. The graph below shows the demand for Ben's Miracle Water, the corresponding marginal revenue, and the marginal and average cost of selling the water. 4.2. If Ben is to maximize profit, how many gallons should he sell per week? Once you are satisfied with your positioning of the graph, click the Submit button.