《經(jīng)濟學(xué)原理第三版習(xí)題答案(IV)》由會員分享，可在線閱讀，更多相關(guān)《經(jīng)濟學(xué)原理第三版習(xí)題答案(IV)（9頁珍藏版）》請在裝配圖網(wǎng)上搜索。

1、SOLUTIONS TO TEXT PROBLEMS: Quick Quizzes 1. Farmer McDonald’s opportunity cost is $300, consisting of 10 hours of lessons at $20 an hour that he could have been earning plus $100 in seeds. His accountant would not count the lost banjo-lesson money, only the seeds, worth $100. If McDonald ea

2、rns $200 from selling the crops, then McDonald earns a $100 accounting profit ($200 sales minus $100 cost of seeds) but makes an economic loss of $100 ($200 sales minus $300 opportunity cost). 2. Farmer Jones’s production function is shown in Figure 1 and his total-cost curve is shown in Figure 2

3、. The production function is concave because of diminishing marginal product. As the number of bags of seeds increases, the marginal product declines, and the production function becomes flatter. The total-cost curve is convex, as the curve gets steeper as the amount of production increases. Tha

4、t is also a feature that arises because of diminishing marginal product, since each additional bag of seeds has lower marginal product and thus the cost of producing additional bushels of wheat goes up. Figure 1 Figure 2 3. The average total cost of producing 5 cars is $250,000/5 = $

5、50,000. Since total cost rose from $225,000 to $250,000 when output increased from 4 to 5, the marginal cost of the fifth car is $25,000. The marginal-cost curve and the average-total-cost curve for a typical firm are shown in Figure 3. They cross at the efficient scale because at low levels o

6、f output, marginal cost is below average total cost, so average total cost is falling. But after the two curves cross, marginal cost rises above average total cost, and average total cost starts to rise. So the point of intersection must be the minimum of average total cost. Figure 3 4.

7、The long-run average total cost of producing 9 planes is $9 million/9 = $1 million. The long-run average total cost of producing 10 planes is $9.5 million/10 = $0.95 million. Since the long-run average total cost declines as the number of planes increases, Boeing exhibits economies of scale.

8、Questions for Review 1. The relationship between a firms total revenue, profit, and total cost is profit equals total revenue minus total costs. 2. An accountant would not count the owner’s opportunity cost of alternative employment as an accounting cost. An example is given in the text in wh

9、ich Helen runs a cookie business, but she could instead work as a computer programmer. Because shes working in her cookie factory, she gives up the opportunity to earn $100 per hour as a computer programmer. The accountant ignores this opportunity cost because no money flow occurs. But the cost i

10、s relevant to Helens decision to run the cookie factory. 3. Marginal product is the increase in output that arises from an additional unit of input. Diminishing marginal product means that the marginal product of an input declines as the quantity of the input increases. 4. Figure 4 shows a pr

11、oduction function that exhibits diminishing marginal product of labor. Figure 5 shows the associated total-cost curve. The production function is concave because of diminishing marginal product, while the total-cost curve is convex for the same reason. Figure 4 Figure 5 5. Total cos

12、t consists of the costs of all inputs needed to produce a given quantity of output. It includes fixed costs and variable costs. Average total cost is the cost of a typical unit of output and is equal to total cost divided by the quantity produced. Marginal cost is the cost of producing an additio

13、nal unit of output and is equal to the change in total cost divided by the change in quantity. An additional relation between average total cost and marginal cost is that whenever marginal cost is less than average total cost, average total cost is declining; whenever marginal cost is greater than

14、average total cost, average total cost is rising. 6. Figure 6 shows the marginal-cost curve and the average-total-cost curve for a typical firm. It has three main features: (1) marginal cost is rising; (2) average total cost is U-shaped; and (3) whenever marginal cost is less than average total

15、 cost, average total cost is declining; whenever marginal cost is greater than average total cost, average total cost is rising. Marginal cost is rising for output greater than a certain quantity because in the short run the firm must hire additional labor to produce more output without being able

16、to buy additional equipment. The average total cost curve is U-shaped because the firm initially is able to spread out fixed costs over additional units, but as quantity increases, it costs more to increase quantity further because some important input is limited. Marginal cost and average total c

17、ost have the relationship they do because marginal cost pulls average total cost in the same direction. The marginal cost and average total cost curves intersect at the minimum of average total cost; that quantity is the efficient scale. Figure 6 7. In the long run, a firm can adjust the

18、factors of production that are fixed in the short run; for example, it can increase the size of its factory. As a result, the long-run average-total-cost curve has a much flatter U-shape than the short-run average-total-cost curve. In addition, the long-run curve lies along the lower envelope of t

19、he short-run curves. 8. Economies of scale exist when long-run average total cost falls as the quantity of output increases, which occurs because of specialization among workers. Diseconomies of scale exist when long-run average total cost rises as the quantity of output increases, which occurs

20、because of coordination problems inherent in a large organization. Problems and Applications 1. a. opportunity cost; b. average total cost; c. fixed cost; d. variable cost; e. total cost; f. marginal cost. 2. a. The opportunity cost of something is what must be forgone to acquire it.

21、 b. The opportunity cost of running the hardware store is $550,000, consisting of $500,000 to rent the store and buy the stock and a $50,000 opportunity cost, since your aunt would quit her job as an accountant to run the store. Since the total opportunity cost of $550,000 exceeds revenue of $510,0

22、00, your aunt should not open the store, as her profit would be negativeshe would lose money. 3. a. Since you would have to pay for room and board whether you went to college or not, that portion of your college payment is not an opportunity cost. b. The explicit opportunity cost is the cost o

23、f tuition and books. c. An implicit opportunity cost is the cost of your time. You could work at a job for pay rather than attend college. The wages you give up represent an opportunity cost of attending college. 4. a. The following table shows the marginal product of each hour spent fishing

24、: Hours Fish Fixed Cost Variable Cost Total Cost Marginal Product 0 0 $10 $0 $10 --- 1 10 10 5 15 10 2 18 10 10 20 8 3 24 10 15 25 6 4 28 10 20 30 4 5 30 10 25 25 2 b. Figure 7 graphs the fishermans production funct

25、ion. The production function becomes flatter as the number of hours spent fishing increases, illustrating diminishing marginal product. Figure 7 c. The table shows the fixed cost, variable cost, and total cost of fishing. Figure 8 shows the fishermans total-cost curve. It slopes up be

26、cause catching additional fish takes additional time. The curve is convex because there are diminishing returns to fishing timeeach additional hour spent fishing yields fewer additional fish. Figure 8 5. Here is the table of costs: Workers Output Marginal Product Total Cost Averag

27、e Total Cost Marginal Cost 0 0 --- $200 --- --- 1 20 20 300 $15.00 $5.00 2 50 30 400 8.00 3.33 3 90 40 500 5.56 2.50 4 120 30 600 5.00 3.33 5 140 20 700 5.00 5.00 6 150 10 800 5.33 10.00 7 155 5 900 5.81 20.00 a. See table for marginal prod

28、uct. Marginal product rises at first, then declines because of diminishing marginal product. b. See table for total cost. c. See table for average total cost. Average total cost is U-shaped. When quantity is low, average total cost declines as quantity rises; when quantity is high, average

29、 total cost rises as quantity rises. d. See table for marginal cost. Marginal cost is also U-shaped, but rises steeply as output increases. This is due to diminishing marginal product. e. When marginal product is rising, marginal cost is falling, and vice versa. f. When marginal cost

30、is less than average total cost, average total cost is falling; the cost of the last unit produced pulls the average down. When marginal cost is greater than average total cost, average total cost is rising; the cost of the last unit produced pushes the average up. 6. Fixed costs include the cos

31、t of owning or renting a car to deliver the bagels and the cost of advertising; they are fixed costs because they do not vary with output. Variable costs include the cost of the bagels and gas for the car, since those costs will increase as output increases. 7. a. The fixed cost is $300, since f

32、ixed cost equals total cost minus variable cost. b. Quantity Total Cost Variable Cost Marginal Cost (using total cost) Marginal Cost (using variable cost) 0 $300 $0 --- --- 1 350 50 $50 $50 2 390 90 40 40 3 420 120 30 30 4 450 150 30 30 5 490 190 40 40 6 5

33、40 240 50 50 Marginal cost equals the change in total cost or the change in variable cost. That is because total cost equals variable cost plus fixed cost and fixed cost does not change as the quantity changes. So as quantity increases, the increase in total cost equals the increase in varia

34、ble cost and both are equal to marginal cost. 8. a. The fixed cost of setting up the lemonade stand is $200. The variable cost per cup is 50 cents. Figure 9 b. The following table shows total cost, average total cost, and marginal cost. These are plotted in Figure 9.  Quantity T

35、otal Cost Average Total Cost Marginal Cost 0 $200 --- --- 1 208 $208 $8 2 216 108 8 3 224 74.7 8 4 232 58 8 5 240 48 8 6 248 41.3 8 7 256 36.6 8 8 264 33 8 9 272 30.2 8 10 280 28 8 9. The following table illustrates average fixed cost (AFC), average v

36、ariable cost (AVC), and average total cost (ATC) for each quantity. The efficient scale is 4 houses per month, since that minimizes average total cost. Quantity Variable Cost Fixed Cost Total Cost Average Fixed Cost Average Variable Cost Average Total Cost 0 $0 $200 $200 --- --- ---

37、 1 10 200 210 $200 $10 $210 2 20 200 220 100 10 110 3 40 200 240 66.7 13.3 80 4 80 200 280 50 20 70 5 160 200 360 40 32 72 6 320 200 520 33.3 53.3 86.7 7 640 200 840 28.6 91.4 120 10. a. The following table shows average variable cost (AVC), averag

38、e total cost (ATC), and marginal cost (MC) for each quantity. Quantity Variable Cost Total Cost Average Variable Cost Average Total Cost Marginal Cost 0 $0 $30 --- --- --- 1 10 40 $10 $40 $10 2 25 55 12.5 27.5 15 3 45 75 15 25 20 4 70 100 17.5 25 25 5 100 130

39、 20 26 30 6 135 165 22.5 27.5 35 b. Figure 10 graphs the three curves. The marginal cost curve is below the average total cost curve when output is less than 4, as average total cost is declining. The marginal cost curve is above the average total cost curve when output is above 4, as

40、average total cost is rising. The marginal cost curve lies above the average variable cost curve. Figure 10 11. The following table shows quantity (Q), total cost (TC), and average total cost (ATC) for the three firms: Firm A Firm B Firm C Quantity TC ATC TC ATC TC ATC

41、 1 60 60 11 11 21 21 2 70 35 24 12 34 17 3 80 26.7 39 13 49 16.3 4 90 22.5 56 14 66 16.5 5 100 20 75 15 85 17 6 110 18.3 96 16 106 17.7 7 120 17.1 119 17 129 18.4 Firm A has economies of scale since average total cost declines as output increases. Firm B has diseconomies of scale since average total cost rises as output rises. Firm C has economies of scale for output from 1 to 3, then diseconomies of scale for greater levels of output. 249 / 9文檔可自由編輯打印