A company estimates that it can sell 5000 units each week of its product if it prices each unit at $ 15 . However, its weekly number of sales will increase by 100 units for each 0.10 decrease in price. The company has fixed costs of $ 1000 . The cost to make each unit is $ 1.80 . Find the level of production that maximizes the company's profit if the company must produce and sell between and including 4000 and 12000 . What is the maximum profit?