1) Firms aim to maximize profits by producing at the quantity where marginal cost equals marginal revenue. 2) A firm's costs include explicit costs like wages as well as implicit opportunity costs. Total costs are used to calculate economic profit. 3) As a firm's production increases, its marginal costs will rise due to diminishing returns. Average costs first fall then rise, creating a U-shaped average total cost curve.

1. 5 FIRM BEHAVIOR AND THE ORGANIZATION OF INDUSTRY

2. 13 The Costs of Production

11. Figure 1 Economic versus Accountants Copyright © 2004 South-Western How an Economist Views a Firm How an Accountant Views a Firm Revenue Total opportunity costs Revenue Economic profit Implicit costs Explicit costs Explicit costs Accounting profit

12. Table 1 A Production Function and Total Cost: Hungry Helen’s Cookie Factory Copyright©2004 South-Western

16. Figure 2 Hungry Helen’s Production Function Copyright © 2004 South-Western Quantity of Output (cookies per hour) 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 Number of Workers Hired 0 1 2 3 4 5 Production function

19. Table 1 A Production Function and Total Cost: Hungry Helen’s Cookie Factory Copyright©2004 South-Western

20. Figure 3 Hungry Helen’s Total-Cost Curve Copyright © 2004 South-Western Total Cost $80 70 60 50 40 30 20 10 Quantity of Output (cookies per hour) 0 10 20 30 150 130 110 90 70 50 40 140 120 100 80 60 Total-cost curve

24. Table 2 The Various Measures of Cost: Thirsty Thelma’s Lemonade Stand Copyright©2004 South-Western

27. Average Costs

28. Table 2 The Various Measures of Cost: Thirsty Thelma’s Lemonade Stand Copyright©2004 South-Western

30. Marginal Cost

31. Marginal Cost Thirsty Thelma’s Lemonade Stand

32. Figure 4 Thirsty Thelma’s Total-Cost Curves Copyright © 2004 South-Western Total Cost $15.00 14.00 13.00 12.00 11.00 10.00 9.00 8.00 7.00 6.00 5.00 4.00 3.00 2.00 1.00 Quantity of Output (glasses of lemonade per hour) 0 1 4 3 2 7 6 5 9 8 10 Total-cost curve

33. Figure 5 Thirsty Thelma’s Average-Cost and Marginal-Cost Curves Copyright © 2004 South-Western Costs $3.50 3.25 3.00 2.75 2.50 2.25 2.00 1.75 1.50 1.25 1.00 0.75 0.50 0.25 Quantity of Output (glasses of lemonade per hour) 0 1 4 3 2 7 6 5 9 8 10 MC ATC AVC AFC

35. Figure 5 Thirsty Thelma’s Average-Cost and Marginal-Cost Curves Copyright © 2004 South-Western Costs $3.50 3.25 3.00 2.75 2.50 2.25 2.00 1.75 1.50 1.25 1.00 0.75 0.50 0.25 Quantity of Output (glasses of lemonade per hour) 0 1 4 3 2 7 6 5 9 8 10 MC

38. Figure 5 Thirsty Thelma’s Average-Cost and Marginal-Cost Curves Copyright © 2004 South-Western Costs $3.50 3.25 3.00 2.75 2.50 2.25 2.00 1.75 1.50 1.25 1.00 0.75 0.50 0.25 Quantity of Output (glasses of lemonade per hour) 0 1 4 3 2 7 6 5 9 8 10 ATC

41. Figure 5 Thirsty Thelma’s Average-Cost and Marginal-Cost Curves Copyright © 2004 South-Western Costs $3.50 3.25 3.00 2.75 2.50 2.25 2.00 1.75 1.50 1.25 1.00 0.75 0.50 0.25 Quantity of Output (glasses of lemonade per hour) 0 1 4 3 2 7 6 5 9 8 10 ATC MC

43. Big Bob’s Cost Curves

44. Figure 6 Big Bob’s Cost Curves Copyright © 2004 South-Western (a) Total-Cost Curve $18.00 16.00 14.00 12.00 10.00 8.00 6.00 4.00 Quantity of Output (bagels per hour) TC 4 2 6 8 14 12 10 2.00 Total Cost 0

45. Figure 6 Big Bob’s Cost Curves Copyright © 2004 South-Western (b) Marginal- and Average-Cost Curves Quantity of Output (bagels per hour) Costs $3.00 2.50 2.00 1.50 1.00 0.50 0 4 2 6 8 14 12 10 MC ATC AVC AFC

49. Figure 7 Average Total Cost in the Short and Long Run Copyright © 2004 South-Western Quantity of Cars per Day 0 Average Total Cost 1,200 $12,000 ATC in short run with small factory ATC in short run with medium factory ATC in short run with large factory ATC in long run

51. Figure 7 Average Total Cost in the Short and Long Run Copyright © 2004 South-Western Quantity of Cars per Day 0 Average Total Cost 1,200 $12,000 1,000 10,000 Economies of scale ATC in short run with small factory ATC in short run with medium factory ATC in short run with large factory ATC in long run Diseconomies of scale Constant returns to scale