A graph shows Price on the vertical axis and Quantity on the horizontal axis. The Demand curve passes through 600 units for $18 and 900 units for $15. The MC curve passes through 600 units for $4 and 900 units for $6. The MR curve passes through 600 units for $12 and 900 units for $6. The ATC curve passes through 900 units for $8. According to the graph, what will be the firm's total revenue if it is maximizing profits