A retired auto mechanic hopes to open a rustproofing shop. Customers would be local new car dealers. Two locations are being considered one in the center of the city and one on the outskirts. The central city location would involve fixed monthly costs of $7000 and labor, materials, and transportation costs of $30 per car. The outside location would have fixed monthly cost of $4700 and labor, materials and transportation costs of $40 per car. Dealer price at either location will be $90 per car At what volume of output will the two sites yield the same monthly profit?