Visitation to lakes for recreation purposes varies directly with the population of the nearest city or town and inversely with the distance between the lake and city. Use the data below to develop a regression equation to predict visitation (V) in person-days per year, using as predictors the population (P) of the nearby town and the distance (D) in miles between the lake and the city.

D P V 10 10,500 22,000 22 27,500 98,000 31 18,000 24,000 18 9,000 33,000 28 31,000 41,000 12 34,000 140,000 21 22,500 78,000 13 19,000 110,000 33 12,000 13,000