To pour a concrete sidewalk takes 2 hours of preparation nd 3 hours of finishing. To pour a concrete patio takes 4 hours of preparation and 3 hours of finishing. ABC Concrete Company makes a profit of $450 on a sidewalks and $700 on a patio. How many sidewalks and patios should the company construct to maximize its profit? Set up a system of inequalities for this problem, identify all variables used, and give the objective function, but do not solve.