The graph presents the costs and revenue for a purely competitive firm, where the market price is equal to $400 per unit of output. Use this information to determine the profit?maximizing output and profit for thisfirm.

What is the profit?maximizing output of this purely competitive firm? Round the answer to the nearest wholenumber.

Cost and revenue $800 (13,800) 750 700 Marginal cost 650 600 Average total cost (12,600) 550 500 (4,500) (6,450) (12,450) 450 (10,400) 400 350 Marginal revenue (9,350) 300 (6,250) 250 Average variable cost (4,200) 200 150 (1,150) 100 50 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Units of output