A maker of fine preserves earns $15 profit on its premium brand x1 and $6 profit on its standard brand x2. The premium-brand preserves take 7.5 minutes for peeling, 20 minutes for stewing, and 8 minutes for canning. The standard-brand preserves take 5 minutes for peeling, 30 minutes for stewing, and 2 minutes for canning. The manufacturer has 150 minutes for peeling, 540 minutes for stewing, and 120 minutes for canning. Reduce the data to equations and inequalities suitable for finding the combination of brands that will maximize profit.