A merchant plans to sell two models of MP3 players at prices of $225 and $250. The $225 model yields a profit of $30 per unit and the $250 model yields a profit of $31 per unit. The merchant estimates that the total monthly demand will not exceed 275 units. The merchant does not want to invest more than $63,000 in inventory for these products. What is the optimal inventory level for each model? What is the optimal profit?