A manufacturing company produces four different products: Product A, Product B, Product C, and Product D. The company's fixed costs are $300,000 per month. The variable costs per unit for Product A, Product B, Product C, and Product D are $20, $25, $30, and $35 respectively. If the selling prices per unit for Product A, Product B, Product C, and Product D are $50, $60, $70, and $80 respectively, and the company aims to maximize profit, how many units of each product should it produce and sell?