A company estimates that it can sell 4, 000 units each month of its product if it prices each unit at $65. However, its monthly number of sales will increase by 5 units for each $0.10 decrease in price. The company has fixed costs of $500. The cost to make each unit is $4.40. Find the level of production that maximizes the company's profit. They should produce | units at a price of $ 1, which will yield a profit of $