Mounting Biking Specialists makes two types of bicycles: mountain bikes and road bikes. A mountain bike sells for $350, and a road bike sells for $250. The marketing department recommends that at least 500 bikes of each type be produced each day. A mountain bike requires 3 labor-hours in the fabrication department and 2 labor hours in the assembly department. A road bike requires 2 labor hours in the fabrication department and 2 labor-hours in the assembly department. Each bike needs 1 hour in the quality-testing department. There are a total of 4,000, 3,000 and 1,000 hours available in the fabrication, assembly, and testing departments, respectively. Formulate this information as a revenue-maximizing linear programming problem.