To achieve a maximum profit, the cost of an item should be as low as possible and the revenue on the item should be as high as possible. The least possible cost of the car is $ 8,000, and the greatest possible selling price of the car is $ 18,000. The greatest profit on one car is thus $ 18,000 − $ 8,000= $ 10,000. The greatest profit on 10 cars is thus $ 10,000 × 10 = $ 100,000.