Four products are processed successively on two machines. The manufacturing times in hours per unit of each product are tabulated below for the two machines. Time per unit (hours) Machine 1 Product 1 Product 2 2 2 3 3 Product 3 4 Product 4 2 2 1 2 The total cost of producing a unit of each product is based directly on the machine time. Assume the cost per hour for machines 1 and 2 are $10 and $15. The total hours budgeted for all the products on machine 1 and 2 are 500 and 380. If the sale price per unit for products 1, 2, 3, and 4 are $65, $70, $55, and $45, formulate the problem as a linear programming model to maximize total net profit.