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第三章6．下表描述了Baseballia国两个城市的生产可能性：一个工人每小时生产的红补袜子量一个工人每小时生产的白袜子量A．没有贸易，波士顿一双白袜子价格（用红袜子表示）是多少芝加哥11双白袜子价格是多少答：没有贸易时，波士顿1 双白袜子价格是1 双红袜子，芝加哥1 双白袜子价格是2 双红袜子。
B．在每种颜色的袜子生产上，哪个城市有绝对优势哪个城市有比较优势答：波士顿在生产红、白袜子上都有绝对优势。
波士顿在生产白袜子上有比较优势，芝加哥在生产红袜子上有比较优势。
C．如果这两个城市相互交易，两个城市将分别出口哪种颜色的袜子答：如果它们相互交易，波士顿将出口白袜子，而芝加哥出口红袜子。
D．可以进行交易的价格范围是多少答：白袜子的最高价格是2 双红袜子，最低价格是1 双红袜子。
红袜子的最高价格是1 双白袜子，最低价格是1／2 双白袜子。
7．假定一个美国工人每年能生产100件衬衣或20台电脑，而一个中国工人每年能生产100件衬衣或10台电脑。
A．画出这两个国家的生产可能性边界。
假定没有贸易，每个国家的工人各用一半的时间生产两种物品，在你的图上标出这一点。
答：两个国家的生产可能性边界如图3 一4 所示。
如果没有贸易，一个美国工人把一半的时间用于生产每种物品，则能生产50 件衬衣、10 台电脑；同样，一个中国工人则能生产50 件衬衣、5 台电脑。
图3 一4 生产可能性边界B．如果这两个国家进行贸易，哪个国家将出口衬衣举出一个具体的数字例子，并在你的图上标出。
哪一个国家将从贸易中获益解释原因。
答：中国将出口衬衣。
对美国而言，生产一台电脑的机会成本是5 件衬衣，而生产一件衬衣的机会成本为1/5 台电脑。
对中国而言，生产一台电脑的机会成本是10 件衬衣，而生产一件衬衣的机会成本为1/10 台电脑。
因此，美国在生产电脑上有比较优势，中国在生产衬衣上有比较优势，所以中国将出口衬衣。
衬衣的价格在1/5 到1/10 台电脑之间。
曼昆《经济学原理（微观经济学分册）》课后习题详解（第7篇）【圣才出品】第7篇深⼊研究的论题第21章消费者选择理论⼀、概念题1．预算约束线（budget constraint ）答：预算约束线⼜称消费可能线和价格线，指对消费者可以承受（在消费者收⼊和消费者希望购买的物品价格既定时）的消费组合的限制。
预算约束线表⽰消费者⽀付得起的消费组合。
假定以I 表⽰消费者的既定收⼊，以P 1和P 2分别表⽰商品1和商品2的价格，以X 1和X 2分别表⽰商品1和商品2的数量，那么，相应的预算等式为：P 1X 1＋P 2X 2＝I 。
上式表⽰：消费者的全部收⼊等于他购买商品1和商品2的总⽀出。
⽽且，可以⽤1I P 和2I P 来分别表⽰全部收⼊仅购买商品1或商品2的数量，它们分别表⽰预算约束线的横截距和纵截距。
此外，上式还可以改写成如下形式：12122P I X X P P =?+。
式中的预算约束线⽅程表明，预算约束线的斜率为12P P ?，纵截距为2I P 。
2．⽆差异曲线（indifference curve ）答：⽆差异曲线指带给消费者相同满⾜程度的消费组合的⼀条曲线。
它表⽰消费者在⼀定偏好、⼀定技术条件和⼀定资源条件下选择商品时，对不同组合商品的满⾜程度是没有区别的。
与⽆差异曲线相对应的效⽤函数为：U ＝f （X 1，X 2）。
其中，X 1、X 2分别为商品1和商品2的消费数量；U 是常数，表⽰某个效⽤⽔平。
由于⽆差异曲线表⽰的是序数效⽤，所以，这⾥的U 只需表⽰某⼀个效⽤⽔平，⽽不在乎其具体数值的⼤⼩。
有的西⽅经济学者称这种效⽤⽔平为效⽤指数。
⽆差异曲线可以表⽰为图21-1所⽰。
在⼀个坐标系内，⽆差异曲线有⽆数条，图21-2中显⽰的只是其中的三条。
图中的横轴表⽰商品1的数量X1，纵轴表⽰商品2的数量X2，I、I′、I″分别代表三条⽆差异曲线。
图中的每⼀条⽆差异曲线上的任何⼀点，如⽆差异曲线I″上的A、B、C、D、E 和F点所代表的商品组合给消费者带来的效⽤⽔平都是相等的。
第1篇导言第1章经济学十大原理一、概念题1．稀缺性（scarcity）答：经济学研究的问题和经济物品都是以稀缺性为前提的。
稀缺性指在给定的时间内，相对于人的需求而言，经济资源的供给总是不足的，也就是资源的有用性与有限性。
人类消费各种物品的欲望是无限的，满足这种欲望的物品，有的可以不付出任何代价而随意取得，称之为自由物品，如阳光和空气；但绝大多数物品是不能自由取用的，因为世界上的资源（包括物质资源和人力资源）是有限的，这种有限的、为获取它必须付出某种代价的物品，称为“经济物品”。
正因为稀缺性的客观存在，地球上就存在着资源的有限性和人类的欲望与需求的无限性之间的矛盾。
经济学的一个重要研究任务就是：“研究人们如何进行抉择，以便使用稀缺的或有限的生产性资源（土地、劳动、资本品如机器、技术知识）来生产各种商品，并把它们分配给不同的社会成员进行消费。
”也就是从经济学角度来研究使用有限的资源来生产什么、如何生产和为谁生产的问题。
2．经济学（economics）答：经济学是研究如何将稀缺的资源有效地配置给相互竞争的用途，以使人类的欲望得到最大限度满足的科学。
时下经常见诸国内报刊文献的“现代西方经济学”一词，大多也都在这个意义上使用。
自从凯恩斯的名著《就业、利息和货币通论》于1936年发表之后，西方经济学界对经济学的研究便分为两个部分：微观经济学与宏观经济学。
微观经济学是以单个经济主体（作为消费者的单个家庭或个人，作为生产者的单个厂商或企业，以及单个产品或生产要素市场）为研究对象，研究单个经济主体面对既定的资源约束时如何进行选择的科学。
宏观经济学则以整个国民经济为研究对象，主要着眼于对经济总量的研究。
3．效率（efficiency）答：效率指人们在实践活动中的产出与投入之比值，或者是效益与成本之比值，如果比值大，效率就高；反之，比值小，效率就低。
效率与产出或者收益的大小成正比，而与成本或投入成反比，也就是说，如果想提高效率，必须降低成本或投入，提高收益或产出。
问题与应用1．描写下列每种情况所面临的权衡取舍：A．一个家庭决定是否买一辆新车。
答：如果买新车就要减少家庭其他方面的开支，如：外出旅行，购置新家具；如果不买新车就享受不到驾驶新车外出的方便和舒适。
B．国会议员决定对国家公园支出多少。
答：对国家公园的支出数额大，国家公园的条件可以得到改善，环境会得到更好的保护。
但同时，政府可用于交通、邮电等其他公共事业的支出就会减少。
C．一个公司总裁决定是否新开一家工厂。
答：开一家新厂可以扩大企业规模，生产更多的产品。
但可能用于企业研发的资金就少了。
这样，企业开发新产品、利用新技术的进度可能会减慢。
D．一个教授决定用多少时间备课。
0答：教授若将大部分时间用于自己研究，可能会出更多成果，但备课时间减少影响学生授课质量。
E．一个刚大学毕业的学生决定是否去读研究生。
答：毕业后参加工作，可即刻获取工资收入；但继续读研究生，能接受更多知识和未来更高收益。
2．你正想决定是否去度假。
度假的大部分成本((机票、旅馆、放弃的工资))都用美元来衡量，但度假的收益是心理的。
你将如何比较收益与成本呢??答：这种心理上的收益可以用是否达到既定目标来衡量。
对于这个行动前就会作出的既定目标，我们一定有一个为实现目标而愿意承担的成本范围。
在这个可以承受的成本范围内，度假如果满足了既定目标，如：放松身心、恢复体力等等，那么，就可以说这次度假的收益至少不小于它的成本。
3．你正计划用星期六去从事业余工作，但一个朋友请你去滑雪。
去滑雪的真实成本是什么？现在假设你已计划这天在图书馆学习，这种情况下去滑雪的成本是什么？请解释之。
答：去滑雪的真实成本是周六打工所能赚到的工资，我本可以利用这段时间去工作。
如果我本计划这天在图书馆学习，那么去滑雪的成本是在这段时间里我可以获得的知识。
曼昆《经济学原理》（微观）第五版测试题库（14）（1）Chapter 14Firms in Competitive MarketsTRUE/FALSE1. For a firm operating in a perfectly competitive industry, total revenue, marginal revenue, and average revenue are all equal.ANS: F DIF: 2 REF: 14-1 NAT: AnalyticLOC: Perfect competition TOP: Average revenue | Marginal rev-enueMSC: Interpretive2. For a firm operating in a perfectly competitive industry, marginal reve-nue and average revenue are equal.ANS: T DIF: 2 REF: 14-1 NAT: AnalyticLOC: Perfect competition TOP: Average revenue | Marginal rev-enueMSC: Interpretive3. If a firm notices that its average revenue equals the current market price, that firm must be participating in a competitive market.ANS: F DIF: 2 REF: 14-1 NAT: AnalyticLOC: Perfect competition TOP: Average revenueMSC: Interpretive4. A profit-maximizing firm in a competitive market will increase produc-tion when average revenue exceeds marginal cost. ANS: T DIF: 2 REF: 14-1 NAT: AnalyticLOC: Perfect competition TOP: Average revenueMSC: Interpretive5. Because there are many buyers and sellers in a perfectly competitive market, no one seller can influence the market price. ANS: T DIF: 1 REF: 14-1 NAT: AnalyticLOC: Perfect competition TOP: Competitive marketsMSC: Definitional6. Firms operating in perfectly competitive markets try to maximize prof-its.ANS: T DIF: 2 REF: 14-1 NAT: AnalyticLOC: Perfect competition TOP: Profit maximization929MSC: Applicative7. In competitive markets, firms that raise their prices are typically re-warded with larger profits.ANS: F DIF: 2 REF: 14-1 NAT: AnalyticLOC: Perfect competition TOP: Competitive marketsMSC: Interpretive8. When an individual firm in a competitive market increases its produc-tion, it is likely that the market price will fall. ANS: F DIF: 2 REF: 14-1 NAT: AnalyticLOC: Perfect competition TOP: Competitive marketsMSC: Interpretive9. In a competitive market, firms are unable to differentiate their product from that of other producers.ANS: T DIF: 1 REF: 14-1 NAT: AnalyticLOC: Perfect competition TOP: Competitive marketsMSC: Interpretive10. Firms in a competitive market are said to be price takers because there are many sellers in the market and the goods offered by the firms are very similar if not identical.ANS: T DIF: 2 REF: 14-1 NAT: AnalyticLOC: Perfect competition TOP: Competitive marketsMSC: Interpretive11. A firm's incentive to compare marginal revenue and marginal cost is an application of the principle that rational people think at the margin. ANS: T DIF: 1 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Profit maximizationMSC: Interpretive12. By comparing the marginal revenue and marginal cost from each unit produced, a firm in a competitive market can determine the profit-maximizing level of production.ANS: T DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Profit maximizationMSC: Interpretiveword⽂档可⾃由复制编辑Chapter 14/Firms in Competitive Markets 931 13. Firms operating in perfectly competitive markets produce an output level where marginal revenue equals marginal cost.ANS: T DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Marginal revenueMSC: Applicative14. A firm is currently producing 100 units of output per day. The man-ager reports to the owner that producing the 100th unit costs the firm $5. The firm can sell the 100th unit for $4.75. The firm should continue to pro-duce 100 units in order to maximize its profits (or minimize its losses). ANS: F DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Profit maximizationMSC: Analytical15. A firm is currently producing 100 units of output per day. The man-ager reports to the owner that producing the 100th unit costs the firm $5. The firm can sell the 100th unit for $5. The firm should continue to produce 100 units in order to maximize its profits (or minimize its losses).ANS: T DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Profit maximizationMSC: Analytical16. A firm is currently producing 100 units of output per day. The man-ager reports to the owner that producing the 100th unit costs the firm $5. The firm can sell the unit for $6. The firm should produce more than 100 units in order to maximize its profits (or minimize its losses).ANS: T DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Profit maximizationMSC: Analytical17. A dairy farmer must be able to calculate sunk costs in order to deter-mine how much revenue the farm receives for the typical gallon of milk. ANS: F DIF: 1 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Sunk costs MSC: I nterpretive18. Because nothing can be done about sunk costs, they are irrelevant to decisions about business strategy.ANS: T DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Sunk costs MSC: I nterpretive19. A miniature golf course is a good example of where fixed costs be-come relevant to the decision of when to open and when to close for the season.ANS: F DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Sunk costs MSC: I nterpretive20. A popular resort restaurant will maximize profits if it chooses to stay open during the less-crowded “off season” when its total revenues exceed its variable costs.ANS: T DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Sunk costs MSC: I nterpretive21. All firms maximize profits by producing an output level where marginal revenue equals marginal cost; for firms operating in perfectly competitive in-dustries, maximizing profits also means producing an output level where price equals marginal cost.ANS: T DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Profit maximizationMSC: Interpretive22. A firm operating in a perfectly competitive industry will continue to op-erate in the short run but earn losses if the market price is less than that firm’s average total cost but greater than the firm’s average variable cost. ANS: T DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Supply curveMSC: Interpretive23. A firm operating in a perfectly competitive industry will continue to op-erate in the short run but earn losses if the market price is less than that firm’s average variable co st.ANS: F DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Supply curveMSC: Interpretive24. A firm operating in a perfectly competitive industry will shut down in the short run but earn losses if the market price is less than that firm’s aver-age variable cost.ANS: T DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Supply curveMSC: Interpretiveword⽂档可⾃由复制编辑Chapter 14/Firms in Competitive Markets 933 25. In the short run, a firm should exit the industry if its marginal cost ex-ceeds its marginal revenue.ANS: F DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Supply curveMSC: Interpretive26. In making a short-run profit-maximizing production decision, the firm must consider both fixed and variable cost. ANS: F DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Profit maximizationMSC: Interpretive27. A firm will shut down in the short run if revenue is not sufficient to cov-er its variable costs of production.ANS: T DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Shut down MSC: I nterpretive28. Suppose a firm is considering producing zero units of output. We call this shutting down in the short run and exiting an industry in the long run. ANS: T DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Shut down MSC: I nterpretive29. Suppose a firm is considering producing zero units of output. We call this exiting an industry in the short run and shutting down in the long run. ANS: F DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Shut down MSC: I nterpretive30. A firm will shut down in the short run if revenue is not sufficient to cov-er all of its fixed costs of production.ANS: F DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Shut down MSC: I nterpretive31. The supply curve of a firm in a competitive market is the average va-riable cost curve above the minimum of marginal cost.ANS: F DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Supply curveMSC: Interpretive32. When a profit-maximizing firm in a competitive market experiences rising prices, it will respond with an increase in production.ANS: T DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Profit maximizationMSC: Interpretive33. The marginal firm in a competitive market will earn zero economic profit in the long run.ANS: T DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Economic profitMSC: Interpretive34. A profit-maximizing firm in a competitive market will earn zero ac-counting profits in the long run.ANS: F DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Accounting profitMSC: Interpretive35. In the long run, when price is less than average total cost for all possi-ble levels of production, a firm in a competitive market will choose to exit (or not enter) the market.ANS: T DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Profit maximizationMSC: Interpretive36. In the long run, when price is greater than average total cost, some firms in a competitive market will choose to enter the market.ANS: T DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Profit maximizationMSC: Interpretive37. In the long run, a firm should exit the industry if its total costs exceed its total revenues.ANS: T DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Profit maximizationMSC: Interpretive38. When a resource used in the production of a good sold in a competi-tive market is available in only limited quantities, the long-run supply curve is likely to be upward sloping.ANS: T DIF: 2 REF: 14-3 NAT: AnalyticLOC: Perfect competition TOP: Supply curveMSC: Interpretiveword⽂档可⾃由复制编辑Chapter 14/Firms in Competitive Markets 935 39. A firm operating in a perfectly competitive industry will continue to op-erate if it earns zero economic profits because it is likely to be earning posi-tive accounting profits.ANS: T DIF: 2 REF: 14-3 NAT: AnalyticLOC: Perfect competition TOP: Competitive marketsMSC: Interpretive40. A firm operating in a perfectly competitive industry will shut down in the short run if its economic profits fall to zero because it is likely to be earn-ing negative accounting profits.ANS: F DIF: 2 REF: 14-3 NAT: AnalyticLOC: Perfect competition TOP: Competitive marketsMSC: Interpretive41. A firm operating in a perfectly competitive market may earn positive, negative, or zero economic profit in the long run. ANS: F DIF: 2 REF: 14-3 NAT: AnalyticLOC: Perfect competition TOP: Long-run supply curveMSC: Interpretive42. A firm operating in a perfectly competitive market may earn positive, negative, or zero economic profit in the short run. ANS: T DIF: 2 REF: 14-3 NAT: AnalyticLOC: Perfect competition TOP: Long-run supply curveMSC: Interpretive43. A firm operating in a perfectly competitive market earns zero economic profit in the long run but remains in business because the firm’s revenues cover the business owners’ opportunity costs.ANS: T DIF: 2 REF: 14-3 NAT: AnalyticLOC: Perfect competition TOP: Zero-profit conditionMSC: Interpretive44. A competitive market will typically experience entry and exit until ac-counting profits are zero.ANS: F DIF: 2 REF: 14-3 NAT: AnalyticLOC: Perfect competition TOP: Zero-profit conditionMSC: Interpretive45. The long-run equilibrium in a competitive market characterized by firms with identical costs is generally characterized by firms operating at effi-cient scale.ANS: T DIF: 2 REF: 14-3 NAT: AnalyticLOC: Perfect competition TOP: Zero-profit conditionMSC: Interpretive46. In the long run, a competitive market with 1,000 identical firms will ex-perience an equilibrium price equal to the minimum of each firm's average total cost.ANS: T DIF: 2 REF: 14-3 NAT: AnalyticLOC: Perfect competition TOP: Zero-profit conditionMSC: Interpretive47. In a long-run equilibrium where firms have identical costs, it is possible that some firms in a competitive market are making a positive economic prof-it.ANS: F DIF: 2 REF: 14-3 NAT: AnalyticLOC: Perfect competition TOP: Zero-profit conditionMSC: Interpretive48. When economic profits are zero in equilibrium, the firm's revenue must be sufficient to cover all opportunity costs. ANS: T DIF: 2 REF: 14-3 NAT: AnalyticLOC: Perfect competition TOP: Zero-profit conditionMSC: Interpretive49. The short-run supply curve in a competitive market must be more elastic than the long-run supply curve.ANS: F DIF: 2 REF: 14-3 NAT: AnalyticLOC: Perfect competition TOP: Supply curveMSC: Interpretive50. The long-run supply curve in a competitive market is more elastic than the short-run supply curve.ANS: T DIF: 2 REF: 14-3 NAT: AnalyticLOC: Perfect competition TOP: Supply curveMSC: InterpretiveSHORT ANSWERword⽂档可⾃由复制编辑Chapter 14/Firms in Competitive Markets 937 1. Describe the difference between average revenue and marginal reve-nue. Why are both of these revenue measures important to a prof-it-maximizing firm?ANS:Average revenue is total revenue divided by the quantity of output. Marginal revenue is the change in total revenue from the sale of each additional unit of output. Marginal revenue is used to determine the profit-maximizing level of production, and average revenue is used to help determine the level of profits. Note that for all firms, price equals average revenue because AR=(PxQ)/Q=P. But only for a firm operating in a perfectly competitive industry does price al-so equal marginal revenue.DIF: 2 REF: 14-1 NAT: Analytic LOC: Perfect competitionTOP: Price MSC: D efinitional2. List and describe the characteristics of a perfectly competitive market. ANS:There are many buyers and sellers in the market. The goods offered by the various sellers are largely the same. Firms can freely enter or exit the market. DIF: 2 REF: 14-1 NAT: Analytic LOC: Perfect competitionTOP: Competitive markets MSC: D efinitional3. Why would a firm in a perfectly competitive market always choose to set its price equal to the current market price? If a firm set its price below the current market price, what effect would this have on the market?ANS:The firm could not sell any more of its product at a lower price than it could sell at the market price. As a result, it would needlessly forgo revenue if it set a price below the market price. If the firm set a higher price, it would not sell anything at all because a competitive market has many sellers who would supply the product at the market price.DIF: 2 REF: 14-1 NAT: Analytic LOC: Perfect competitionTOP: Profit maximization MSC: A nalytical4. Use a graph to demonstrate the circumstances that would prevail in a competitive market where firms are earning economic profits. Can this sce-nario be maintained in the long run? Explain your answer.ANS:In a competitive market where firms are earning economic profits, new firms will have an incentive to enter the market. This entry will expand the number of firms, increase the quantity of the good supplied, and drive down pricesword ⽂档可⾃由复制编辑 and profits. Entry will cease once firms are producing the output level where price equals the minimum of the average total cost curve, meaning that eachfirm earns zero economic profits in the long run.DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Profit maximization MSC: A nalytical5. Explain how a firm in a competitive market identifies the prof-it-maximizing level of production. When should the firm raise production, and when should the firm lower production? ANS:The firm selects the level of output at which marginal revenue is equal tomarginal cost. If MR > MC, profit will increase if the firm increases Q. If MR < MC, profit will increase if the firm decreases Q. DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Profit maximization MSC: A nalytical6. News reports from the western United States occasionally report inci-dents of cattle ranchers slaughtering a large number of newborn calves and burying them in mass graves rather than transporting them to markets. As-suming that this is rational behavior by profit-maximizing "firms," explain what economic factors may influence such behavior.ANS:If the selling price is not sufficient to cover the variable cost of sending the calves to market, this (potentially emotionally upsetting) behavior makes economic sense.DIF: 2 REF: 14-2 NAT: AnalyticLOC: Perfect competition TOP: Profit maximization MSC: A nalytical。
第十二章税制的设计复习题1．在过去的几十年来，政府的增长比经济中的其他部分快还是慢?答：在过去几十年间，政府的增长比经济中其他部分快。
数据表明，美国经济中包括联邦、州和地方政府在内的政府收入在总收人中所占百分比的增长速度快于经济中其他部分。
2．美国联邦政府收入最重要的两个来源是什么?答：美国联邦政府收入最重要的两个来源是个人收入所得税和用于社会保障的工薪税。
3．解释公司利润如何双重纳税。
答：当企业赚到利润时，它要按公司所得税交税；当企业用其利润向公司股东支付股息时，按个人所得税第二次交税。
4．为什么纳税人的税收负担大于政府得到的收入?答：因为纳税人的税收负担除了向政府交纳的税收之外，还包括两种成本：一是税收改变了激励所引起的资源配置扭曲；二是遵守税法的管理负担。
这两种成本没有政府的收入作为补偿。
因此，纳税人的税收负担大于政府得到的收入。
5．为什么一些经济学家支持对消费征税，而不是对收入征税?答：因为对收入征税扭曲了对人们储蓄的激励，鼓励人们少储蓄。
如果政府采取消费税，储蓄起来的全部收入在最后支出前都不征税，就不会扭曲人们的储蓄决策。
6．举出富有的纳税人应该比贫穷纳税人多纳税的两种观点。
答：这方面的观点有受益原则和能力纳税原则。
受益原则认为：人们应该根据他们从政府服务中得到的利益来纳税。
通常富人从公共服务中受益多，他们应该多纳税。
能力纳税原则认为：应该根据一个人所能承受的负担来对这个人征税。
显然，富人的财务承受能力强于穷人，富人应该多纳税。
7．什么是横向平等概念。
为什么运用这个概念是困难的?答：横向平等是指主张有相似支付能力的纳税人应该缴纳等量税收的思想。
这一原则面临的问题是什么决定两个纳税人是相似的。
每个纳税人在许多方面不同，为了评价税收是不是横向平等，必须决定哪些差别对纳税人的支付能力是相关的，哪些是不相关的。
这些相关关系的确定是复杂而困难的。
它不仅涉及经济学问题，还涉及价值观问题，很难说确定的结果是否公平。
rketsWHAT’S NEW IN THE SIXTH EDITION:There are no major changes to this chapter.LEARNING OBJECTIVES:By the end of this chapter, students should understand:the link between buyers’ willingness to pay for a good and the demand curve.how to define and measure consumer surplus.the link between sellers’ costs of producing a good and the supply curve.how to define and measure producer surplus.that the equilibrium of supply and demand maximizes total surplus in a market.CONTEXT AND PURPOSE:Chapter 7 is the first chapter in a three-chapter sequence on welfare economics and market efficiency. Chapter 7 employs the supply and demand model to develop consumer surplus and producer surplus as a measure of welfare and market efficiency. These concepts are then7CONSUMERS, PRODUCERS, AND THEEFFICIENCY OF MARKETSutilized in Chapters 8 and 9 to determine the winners and losers from taxation and restrictions on international trade.The purpose of Chapter 7 is to develop welfare economics—the study of how the allocation of resources affects economic well-being. Chapters 4 through 6 employed supply and demand in a positive framework, which focused on the question, “What is the equilibrium price and quantity in a market” This chapter now addresses the normative question, “Is the equilibrium price and quantity in a market the best possible solution to the resource allocation problem, or is it simply the price and quantity that balance supply and demand” Students will discover that under most circumstances the equilibrium price and quantity is also the one that maximizes welfare.KEY POINTS:Consumer surplus equals buyers’ willingness to pay for a good minus the amount they actually pay for it, and it measures the benefit buyers get from participating in a market.Consumer surplus can be computed by finding the area below the demand curve and above the price.Producer surplus equals the amount sellers receive for their goods minus their costs of production, and it measures the benefit sellers get from participating in a market.Producer surplus can be computed by finding the area below the price and above the supply curve.An allocation of resources that maximizes the sum of consumer and producer surplus is said to be efficient. Policymakers are often concerned with the efficiency, as well as the equality, of economic outcomes.The equilibrium of supply and demand maximizes the sum of consumer and producer surplus.That is, the invisible hand of the marketplace leads buyers and sellers to allocate resources efficiently.Markets do not allocate resources efficiently in the presence of market failures such as market power or externalities.CHAPTER OUTLINE:I. Definition of welfare economics: the study of how the allocation of resources affectseconomic well-being.Students often are confused by the use of the word “welfare.” Remind themthat we are talking about social well-being and not public assistance.II. Consumer SurplusA. Willingness to Pay1. Definition of willingness to pay: the maximum amount that a buyer will pay for agood.2. Example: You are auctioning a mint-condition recording of Elvis Presley’s firstalbum. Four buyers show up. Their willingness to pay is as follows:If the bidding goes to slightly higher than $80, all buyers drop outexcept for John. Because John is willing to pay more than he has to forthe album, he derives some benefit from participating in the market.3. Definition of consumer surplus: the amount a buyer is willing to pay for a goodminus the amount the buyer actually pays for it.4. Note that if you had more than one copy of the album, the price in the auctionJohn and Paul would gain consumer surplus.B. Using the Demand Curve to Measure Consumer Surplus1. We can use the information on willingness to pay to derive a demand curve for therare Elvis Presley album.2. At any given quantity, the price given by the demand curve reflects thewillingness to pay of the marginal buyer. Because the demand curve shows the buyers’ willingness to pay, we can use the demand curve to measure consumer surplus.Figure 23. Consumer surplus can be measured as the area below the demand curve and above theprice.C. How a Lower Price Raises Consumer SurplusFigure 31. As price falls, consumer surplus increases for two reasons.a. Those already buying the product will receive additional consumer surplusbecause they are paying less for the product than before (area A on the graph).b. Because the price is now lower, some new buyers will enter the market andreceive consumer surplus on these additional units of output purchased (area Bon the graph).D. What Does Consumer Surplus MeasureIt is important to stress that consumer surplus is measured in monetaryterms. Consumer surplus gives us a way to place a monetary cost on1. Remember that consumer surplus is the difference between the amount that buyersare willing to pay for a good and the price that they actually pay.2. Thus, it measures the benefit that consumers receive from the good as the buyersthemselves perceive it.ALTERNATIVE CLASSROOM EXAMPLE:Review the material on price ceilings from Chapter 6. Redraw the market for two-bedroom apartments in your town. Draw in a price ceiling below the equilibriumprice.III. Producer SurplusA. Cost and the Willingness to Sell1. Definition of cost: the value of everything a seller must give up to produce agood.You will need to take some time to explain the relationship between theproducers’ willingness to sell and the cost of producing the good. Therelationship between cost and the supply curve is not as apparent as the2. Example: You want to hire someone to paint your house. You accept bids for thework from four sellers. Each painter is willing to work if the price you will pay exceeds her opportunity cost. (Note that this opportunity cost thus represents willingness to sell.) The costs are:3. Bidding will stop when the price gets to be slightly below $600. All sellers willdrop out except for Grandma. Because Grandma receives more than she would require to paint the house, she derives some benefit from producing in the market.4. Definition of producer surplus: the amount a seller is paid for a good minus theseller’s cost of providing it.5. Note that if you had more than one house to paint, the price in the auction wouldend up being higher (a little under $800 in the case of two houses) and both Grandma and Georgia would gain producer surplus.B. Using the Supply Curve to Measure Producer Surplus1. We can use the information on cost (willingness to sell) to derive a supply curvefor house painting services.Price Sellers Quantity Supplied$900 or more Mary, Frida, Georgia, Grandma4$800 to $900Frida, Georgia, Grandma3$600 to $800Georgia, Grandma2$500 to $600Grandma1less than $500None02. At any given quantity, the price given by the supply curve represents the cost ofthe marginal seller. Because the supply curve shows the sellers’ cost (willingness to sell), we can use the supply curve to measure producer surplus.3. Producer surplus can be measured as the area above the supply curve and below theprice.Figure 4Figure 5C. How a Higher Price Raises Producer Surplus1. As price rises, producer surplus increases for two reasons.a. Those already selling the product will receive additional producer surplusbecause they are receiving more for the product than before (area C on thegraph).b. Because the price is now higher, some new sellers will enter the market andreceive producer surplus on these additional units of output sold (area D onthe graph).D. Producer surplus is used to measure the economic well-being of producers, much like Figure 6ALTERNATIVE CLASSROOM EXAMPLE:Review the material on price floors from Chapter 6. Redraw the market for an agricultural product such as corn. Draw in a price support above the equilibriumprice.Then go through:IV. Market EfficiencyA. The Benevolent Social Planner1. The economic well-being of everyone in society can be measured by total surplus,which is the sum of consumer surplus and producer surplus:Total Surplus = Consumer Surplus + Producer SurplusTotal Surplus = (Value to Buyers – Amount Paid by Buyers) + (Amount Received by Sellers – Cost to Sellers)Because the Amount Paid by Buyers = Amount Received by Sellers:2. Definition of efficiency: the property of a resource allocation of maximizing thetotal surplus received by all members of society .3. Definition of equality: the property of distributing economic prosperity uniformlythe members of society .B. Evaluating the Market EquilibriumTotal Surplus = Value to Buyers Cost to SellersFigure 7Now might be a good time to point out that many government policies involvea trade-off between efficiency and equity. When you evaluate government Pretty Woman, Chapter 6. Vivien (Julia Roberts) and Edward (Richard Gere)negotiate a price. Afterward, Vivien reveals she would have accepted a lower price, while Edward admits he would have paid more. If you have done a good job of introducing consumer and producer surplus, you will see the1. At the market equilibrium price:a. Buyers who value the product more than the equilibrium price will purchase theproduct; those who do not, will not purchase the product. In other words, thefree market allocates the supply of a good to the buyers who value it mosthighly, as measured by their willingness to pay.b. Sellers whose costs are lower than the equilibrium price will produce theproduct; those whose costs are higher, will not produce the product. In otherwords, the free market allocates the demand for goods to the sellers who canproduce it at the lowest cost.2. Total surplus is maximized at the market equilibrium.Figure 8a. At any quantity of output smaller than the equilibrium quantity, the value ofthe product to the marginal buyer is greater than the cost to the marginalseller so total surplus would rise if output increases.b. At any quantity of output greater than the equilibrium quantity, the value ofthe product to the marginal buyer is less than the cost to the marginal sellerso total surplus would rise if output decreases.3. Note that this is one of the reasons that economists believe Principle #6: Marketsare usually a good way to organize economic activity.It would be a good idea to remind students that there are circumstanceswhen the market process does not lead to the most efficient outcome.Examples include situations such as when a firm (or buyer) has market powerC. In the News: Ticket Scalping1. Ticket scalping is an example of how markets work to achieve an efficient outcome.2. This article from The Boston Globe describes economist Chip Case’s experiencewith ticket scalping.D. Case Study: Should There Be a Market in Organs1. As a matter of public policy, people are not allowed to sell their organs.a. In essence, this means that there is a price ceiling on organs of $0.b. This has led to a shortage of organs.2. The creation of a market for organs would lead to a more efficient allocation ofresources, but critics worry about the equity of a market system for organs.V. Market Efficiency and Market FailureA. To conclude that markets are efficient, we made several assumptions about how marketsworked.1. Perfectly competitive markets.2. No externalities.B. When these assumptions do not hold, the market equilibrium may not be efficient.C. When markets fail, public policy can potentially remedy the situation.SOLUTIONS TO TEXT PROBLEMS:Quick Quizzes1. Figure 1 shows the demand curve for turkey. The price of turkey is P1and theconsumer surplus that results from that price is denoted CS. Consumer surplus isthe amount a buyer is willing to pay for a good minus the amount the buyeractually pays for it. It measures the benefit to buyers of participating in amarket.Figure 1 Figure 22. Figure 2 shows the supply curve for turkey. The price of turkey is P1and theproducer surplus that results from that price is denoted PS. Producer surplus isthe amount sellers are paid for a good minus the sellers’ cost of providing it(measured by the supply curve). It measures the benefit to sellers ofparticipating in a market.Figure 33. Figure 3 shows the supply and demand for turkey. The price of turkey is P1,consumer surplus is CS, and producer surplus is PS. Producing more turkeys thanthe equilibrium quantity would lower total surplus because the value to themarginal buyer would be lower than the cost to the marginal seller on thoseadditional units.Questions for Review1. The price a buyer is willing to pay, consumer surplus, and the demand curve areall closely related. The height of the demand curve represents the willingness topay of the buyers. Consumer surplus is the area below the demand curve and abovethe price, which equals the price that each buyer is willing to pay minus theprice actually paid.2. Sellers' costs, producer surplus, and the supply curve are all closely related.The height of the supply curve represents the costs of the sellers. Producersurplus is the area below the price and above the supply curve, which equals theprice received minus each seller's costs of producing the good.Figure 43. Figure 4 shows producer and consumer surplus in a supply-and-demand diagram.4. An allocation of resources is efficient if it maximizes total surplus, the sum ofconsumer surplus and producer surplus. But efficiency may not be the only goal ofeconomic policymakers; they may also be concerned about equity the fairness ofthe distribution of well-being.5. The invisible hand of the marketplace guides the self-interest of buyers andsellers into promoting general economic well-being. Despite decentralized decisionmaking and self-interested decision makers, free markets often lead to anefficient outcome.6. Two types of market failure are market power and externalities. Market power maycause market outcomes to be inefficient because firms may cause price and quantityto differ from the levels they would be under perfect competition, which keepstotal surplus from being maximized. Externalities are side effects that are nottaken into account by buyers and sellers. As a result, the free market does notmaximize total surplus.Problems and Applications1. a. Consumer surplus is equal to willingness to pay minus the price paid.Therefore, Melissa’s willingness to pay must be $200 ($120 + $80).b. Her consumer surplus at a price of $90 would be $200 − $90 = $110.c. If the price of an iPod was $250, Melissa would not have purchased one becausethe price is greater than her willingness to pay. Therefore, she would receiveno consumer surplus.2. If an early freeze in California sours the lemon crop, the supply curve for lemonsshifts to the left, as shown in Figure 5. The result is a rise in the price oflemons and a decline in consumer surplus from A + B + C to just A. So consumersurplus declines by the amount B + C.Figure 5 Figure 6In the market for lemonade, the higher cost of lemons reduces the supply oflemonade, as shown in Figure 6. The result is a rise in the price of lemonade anda decline in consumer surplus from D + E + F to just D, a loss of E + F. Note thatan event that affects consumer surplus in one market often has effects on consumersurplus in other markets.3. A rise in the demand for French bread leads to an increase in producer surplus inthe market for French bread, as shown in Figure 7. The shift of the demand curveleads to an increased price, which increases producer surplus from area A to areaA +B + C.Figure 7The increased quantity of French bread being sold increases the demand for flour,as shown in Figure 8. As a result, the price of flour rises, increasing producersurplus from area D to D + E + F. Note that an event that affects producer surplusin one market leads to effects on producer surplus in related markets.Figure 84. a. Bert’s demand schedule is:Price Quantity DemandedMore than $70$5 to $71$3 to $52$1 to $33$1 or less4Bert’s demand curve is shown in Figure 9.Figure 9b. When the price of a bottle of water is $4, Bert buys two bottles of water. Hisconsumer surplus is shown as area A in the figure. He values his first bottleof water at $7, but pays only $4 for it, so has consumer surplus of $3. Hevalues his second bottle of water at $5, but pays only $4 for it, so hasconsumer surplus of $1. Thus Bert’s total consumer surplus is$3 + $1 = $4,which is the area of A in the figure.c. When the price of a bottle of water falls from $4 to $2, Bert buys threebottles of water, an increase of one. His consumer surplus consists of bothareas A and B in the figure, an increase in the amount of area B. He getsconsumer surplus of $5 from the first bottle ($7 value minus $2 price), $3 fromthe second bottle ($5 value minus $2 price), and $1 from the third bottle ($3value minus $2 price), for a total consumer surplus of $9. Thus consumersurplus rises by $5 (which is the size of area B) when the price of a bottle ofwater falls from $4 to $2.5. a. Ernie’s supply schedule for water is:Price Quantity SuppliedMore than $74$5 to $73$3 to $52$1 to $31Less than $10Ernie’s su pply curve is shown in Figure 10.Figure 10b. When the price of a bottle of water is $4, Ernie sells two bottles of water.His producer surplus is shown as area A in the figure. He receives $4 for his first bottle of water, but it costs only $1 to produce, so Ernie has producer surplus of $3. He also receives $4 for his second bottle of water, which costs $3 to produce, so he has producer surplus of $1. Thus Ernie’s total producer surplus is $3 + $1 = $4, which is the area of A in the figure.c. When the price of a bottle of water rises from $4 to $6, Ernie sells threebottles of water, an increase of one. His producer surplus consists of bothareas A and B in the figure, an increase by the amount of area B. He gets producer surplus of $5 from the first bottle ($6 price minus $1 cost), $3 from the second bottle ($6 price minus $3 cost), and $1 from the third bottle ($6 price minus $5 price), for a total producer surplus of $9. Thus producer surplus rises by $5 (which is the size of area B) when the price of a bottle of water rises from $4 to $6.6. a. From Ernie’s supply schedule and Bert’s demand schedule, the quantitydemanded and supplied are:Only a price of $4 brings supply and demand into equilibrium, with an equilibrium quantity of two.b. At a price of $4, consumer surplus is $4 and producer surplus is $4, as shownin Problems 3 and 4 above. Total surplus is $4 + $4 = $8.c. If Ernie produced one less bottle, his producer surplus would decline to $3, asshown in Problem 4 above. If Bert consumed one less bottle, his consumer surplus would decline to $3, as shown in Problem 3 above. So total surplus would decline to $3 + $3 = $6.d. If Ernie produced one additional bottle of water, his cost would be $5, but theprice is only $4, so his producer surplus would decline by $1. If Bert consumed one additional bottle of water, his value would be $3, but the price is $4, so his consumer surplus would decline by $1. So total surplus declines by $1 + $1 = $2.7. a. The effect of falling production costs in the market for stereos results in ashift to the right in the supply curve, as shown in Figure 11. As a result, theequilibrium price of stereos declines and the equilibrium quantity increases.Figure 11b. The decline in the price of stereos increases consumer surplus from area A to A+ B + C + D, an increase in the amount B + C + D. Prior to the shift in supply,producer surplus was areas B + E (the area above the supply curve and below theprice). After the shift in supply, producer surplus is areas E + F + G. Soproducer surplus changes by the amount F + G –B, which may be positive ornegative. The increase in quantity increases producer surplus, while thedecline in the price reduces producer surplus. Because consumer surplus risesby B + C + D and producer surplus rises by F + G – B, total surplus rises by C+ D + F + G.c. If the supply of stereos is very elastic, then the shift of the supply curvebenefits consumers most. To take the most dramatic case, suppose the supplycurve were horizontal, as shown in Figure 12. Then there is no producer surplusat all. Consumers capture all the benefits of falling production costs, withconsumer surplus rising from area A to area A + B.Figure 128. Figure 13 shows supply and demand curves for haircuts. Supply equals demand at aquantity of three haircuts and a price between $4 and $5. Firms A, C, and D shouldcut the hair of Ellen, Jerry, and Phil. Oprah’s willingness to pay is too low andfirm B’s costs are too high, so they do not participate. The maximum totalsurplus is the area between the demand and supply curves, which totals $11 ($8value minus $2 cost for the first haircut, plus $7 value minus $3 cost for thesecond, plus $5 value minus $4 cost for the third).Figure 139. a. The effect of falling production costs in the market for computers results in ashift to the right in the supply curve, as shown in Figure 14. As a result, theequilibrium price of computers declines and the equilibrium quantity increases.The decline in the price of computers increases consumer surplus from area A toA +B +C + D, an increase in the amount B + C + D.Figure 14 Figure 15Prior to the shift in supply, producer surplus was areas B + E (the area abovethe supply curve and below the price). After the shift in supply, producersurplus is areas E + F + G. So producer surplus changes by the amount F + G –B, which may be positive or negative. The increase in quantity increases producer surplus, while the decline in the price reduces producer surplus.Because consumer surplus rises by B + C + D and producer surplus rises by F + G – B, total surplus rises by C + D + F + G.b. Because typewriters are substitutes for computers, the decline in the price ofcomputers means that people substitute computers for typewriters, shifting the demand for typewriters to the left, as shown in Figure 15. The result is a decline in both the equilibrium price and equilibrium quantity of typewriters.Consumer surplus in the typewriter market changes from area A + B to A + C, a net change of C – B. Producer surplus changes from area C + D + E to area E, a net loss of C + D. Typewriter producers are sad about technological advances in computers because their producer surplus declines.c. Because software and computers are complements, the decline in the price andincrease in the quantity of computers means that the demand for softwareincreases, shifting the demand for software to the right, as shown in Figure 16.The result is an increase in both the price and quantity of software. Consumersurplus in the software market changes from B + C to A + B, a net change of A– C. Producer surplus changes from E to C + D + E, an increase of C + D, sosoftware producers should be happy about the technological progress incomputers.Figure 16d. Yes, this analysis helps explain why Bill Gates is one the world’s richestpeople, because his company produces a lot of software that is a complementwith computers and there has been tremendous technological advance in computers.10. a. With Provider A, the cost of an extra minute is $0. With Provider B, the costof an extra minute is $1.b. With Provider A, my friend will purchase 150 minutes [= 150 – (50)(0)]. WithProvider B, my friend would purchase 100 minutes [= 150 – (50)(1)].c. With Provider A, he would pay $120. The cost would be $100 with Provider B.Figure 17d. Figure 17 shows the friend’s demand. With Provider A, he buys 150 minutes andhis consumer surplus is equal to (1/2)(3)(150) – 120 = 105. With Provider B,his consumer surplus is equal to (1/2)(2)(100) = 100.e. I would recommend Provider A because he receives greater consumer surplus.11. a. Figure 18 illustrates the demand for medical care. If each procedure has aprice of $100, quantity demanded will be Q1 procedures.Figure 18b. If consumers pay only $20 per procedure, the quantity demanded will be Q2procedures. Because the cost to society is $100, the number of proceduresperformed is too large to maximize total surplus. The quantity that maximizestotal surplus is Q1 procedures, which is less than Q2.c. The use of medical care is excessive in the sense that consumers get procedureswhose value is less than the cost of producing them. As a result, theeconomy’s total surplus is reduced.d. To prevent this excessive use, the consumer must bear the marginal cost of theprocedure. But this would require eliminating insurance. Another possibilitywould be that the insurance company, which pays most of the marginal cost ofthe procedure ($80, in this case) could decide whether the procedure should beperformed. But the insurance company does not get the benefits of the procedure,so its decisions may not reflect the value to the consumer.。
曼昆微观经济学第五版答案【篇一：曼昆_微观经济学_原理_第五版_课后习题答案(修改)】/p> 4．你在篮球比赛的赌注中赢了100美元。
你可以选择现在花掉它或在利率为55%的银行中存一年。
现在花掉100美元的机会成本是什么呢?答：现在花掉100 美元的机会成本是在一年后得到105 美元的银行支付(利息+本金)。
7．社会保障制度为65岁以上的人提供收入。
如果一个社会保障的领取者决定去工作并赚一些钱，他(或她)所领到的社会保障津贴通常会减少。
a．提供社会保障如何影响人们在工作时的储蓄激励?答：社会保障的提供使人们退休以后仍可以获得收入，以保证生活。
因此，人们不用为不能工作时的生活费而发愁，人们在工作时期的储蓄就会减少。
b．收入提高时津贴减少的政策如何影响65岁以上的人的工作激励??答：这会使65 岁以上的人在工作中不再积极进取。
因为努力工作获得高收入反而会使得到的津贴减少，所以对65 岁以上的人的努力工作的激励减少了。
11．解释下列每一项政府活动的动机是关注平等还是关注效率。
在关注效率的情况下，讨论所涉及的市场失灵的类型。
a．对有线电视频道的价格进行管制。
答：这是关注效率，市场失灵的原因是市场势力的存在。
可能某地只有一家有线电视台，由于没有竞争者，有线电视台会向有线频道的消费者收取高出市场均衡价格的价格，这是垄断。
垄断市场不能使稀缺资源得到最有效的配置。
在这种情况下，规定有线电视频道的价格会提高市场效率。
b．向一些穷人提供可用来购买食物的消费券。
答：这是出于关注平等的动机，政府这样做是想把经济蛋糕更公平地分给每一个人。
c．在公共场所禁止抽烟。
答：这是出于关注效率的动机。
因为公共场所中的吸烟行为会污染空气，影响周围不吸烟者的身体健康，对社会产生了有害的外部性，而外部性正是市场失灵的一种情况，而这也正是政府在公共场所禁止吸烟的原因。
d．把美孚石油公司(它曾拥90%的炼油厂)分拆为几个较小的公司。
答：出于关注效率的动机，市场失灵是由于市场势力。
第三章6．下表描述了Baseballia国两个城市的生产可能性：一个工人每小时生产的红补袜子量一个工人每小时生产的白袜子量A．没有贸易，波士顿一双白袜子价格（用红袜子表示）是多少？芝加哥11双白袜子价格是多少? 答：没有贸易时，波士顿1 双白袜子价格是1 双红袜子，芝加哥1 双白袜子价格是2 双红袜子。
B．在每种颜色的袜子生产上，哪个城市有绝对优势？哪个城市有比较优势??答：波士顿在生产红、白袜子上都有绝对优势。
波士顿在生产白袜子上有比较优势，芝加哥在生产红袜子上有比较优势。
C．如果这两个城市相互交易，两个城市将分别出口哪种颜色的袜子?答：如果它们相互交易，波士顿将出口白袜子，而芝加哥出口红袜子。
D．可以进行交易的价格范围是多少?答：白袜子的最高价格是2 双红袜子，最低价格是1 双红袜子。
红袜子的最高价格是1 双白袜子，最低价格是1／2 双白袜子。
7．假定一个美国工人每年能生产100件衬衣或20台电脑，而一个中国工人每年能生产100件衬衣或10台电脑。
A．画出这两个国家的生产可能性边界。
假定没有贸易，每个国家的工人各用一半的时间生产两种物品，在你的图上标出这一点。
答：两个国家的生产可能性边界如图3 一4 所示。
如果没有贸易，一个美国工人把一半的时间用于生产每种物品，则能生产50 件衬衣、10 台电脑；同样，一个中国工人则能生产50 件衬衣、5 台电脑。
图3 一4 生产可能性边界B．如果这两个国家进行贸易，哪个国家将出口衬衣？举出一个具体的数字例子，并在你的图上标出。
哪一个国家将从贸易中获益？解释原因。
答：中国将出口衬衣。
对美国而言，生产一台电脑的机会成本是5 件衬衣，而生产一件衬衣的机会成本为1/5 台电脑。
对中国而言，生产一台电脑的机会成本是10 件衬衣，而生产一件衬衣的机会成本为1/10 台电脑。
因此，美国在生产电脑上有比较优势，中国在生产衬衣上有比较优势，所以中国将出口衬衣。
衬衣的价格在1/5 到1/10 台电脑之间。
答：供给曲线的高度与卖者的成本相关。
在任何一种数量时，供给曲线给出的价格表示边际卖者的成本。
价格之下和供给曲线以上的面积衡量市场的生产者剩余。
3．在供求图中，标出市场均衡时的生产者剩余和消费者剩余。
答：APE的面积代表消费者剩余；PBE的面积代表生产者剩余。
图7－1供求图4．什么是效率?它是经济决策者的唯一目标吗?答：效率是指资源配置使社会所有成员得到的总剩余最大化的性质。
除了效率外，经济决策者还应该关心平等。
实际上，市场交易的好处很像在市场参与者之间分割一块蛋糕，经济决策者不仅要关心如何将经济蛋糕做大，即效率；还要考虑如何在市场参与者之间分这块蛋糕，这就涉及公平问题。
5．看不见的手有什么作用?答：每一个市场参与者都会尽力追求自己的利益，看不见的手指引他们在相互竞争中达到一个并非他们本意想要达到的目的，这就是市场均衡点。
在均衡点上，消费者剩余和生产者剩余总和最大化，整个社会福利达到最大。
6．说出两种市场失灵的名称。
解释为什么每一种都可能使市场结果无效率。
答：市场失灵包括市场势力和外部性。
如果某一市场上存在市场势力，即只有极少部分(可能是一个)买者或卖者可以控制市场价格，他们就会使价格趋向于对他们这一小部分人有益的水平。
于是，市场价格和数量背离供求平衡，社会福利达不到最大，市场失去效率。
外部性是某些市场参与者的行为对旁观者福利的影响。
它使市场福利还要取决于买者评价和卖者成本之外的其他因素。
由于买者和卖者在决定消费和生产时并没有考虑这种负作用。
所以，从整个社会角度来看，市场均衡可能是无效率的。
问题与应用1．Melissa用120美元购买了一个iPod，并得到了80美元的消费者剩余。
A．她的支付意愿是多少？答：消费者剩余等于支付意愿减去付出的价格。
因此，梅莉莎须支付200美元($120+$80)。
B．如果她在降价销售时买了售价为90美元的iPod，她的消费者剩余会是多少？答：此时，她的消费者剩余为：200-90=110美元。
C．如果iPod的价格是250美元，她的消费者剩余会是多少？答：如果iPod的价格是250美元，其价格大于梅莉莎的支付愿意，因此她不会再买，这时的消费者剩余就为零。
2．加利福尼亚早来的寒流使柠檬变酸。
柠檬市场上消费者剩余会有什么变动？柠檬水市场上消费者剩余会有什么变动？用图形说明你的答案。
答：柠檬变酸，消费者对柠檬的评价下降，需求曲线向左下方移动。
在其他条件不变的情况下，消费者剩余减少。
如图7－2(a)所示，柠檬质量下降，使需求曲线从D1下降到D2，APE是原先的消费者剩余，A′P′E′，是变动后的消费者剩余，△APE>△A′P′E′。
由于柠檬价格的下降，柠檬水的投入成本减少，柠檬水的价格也下降。
在其他条件不变的情况下，柠檬水市场上消费者剩余增加，如图7－2(b)所示。
（a）柠檬市场（b）柠檬水市场图7－2寒流的影响3．假设对法国面包的需求增加。
在法国面包市场上，生产者剩余会发生什么变动？在面粉市场上，生产者剩余会发生什么变动？用图形说明你的答案。
答：由于需求增加，在其他条件不变的情况下，法国面包的价格会上升，市场上的生产者剩余增加。
如图7－3(a)，价格从P1上升的P2，销量从Q1上升到Q2，生产者剩余从面积P l BE1增加到面积P2BE2。
由于面包产量上升，它的生产要素面粉的需求量也会上升。
在其他条件不变的情况下，面粉价格上升，市场上的生产者剩余增加。
如图7－3(b)所示，生产者剩余从面积P1BE1增加到面积P2BE2。
（a）面包市场的生产者剩余（b）面粉市场的生产者剩余图7－3法国面包需求增加的影响4．这是一个热天，Bert口干舌燥。
下面是他对一瓶水的评价：对第一瓶评价7美元对第二瓶评价5美元对第三瓶评价3美元对第四瓶评价1美元A．根据以上信息推导出Bert的需求表。
画出他对瓶装水的需求曲线。
答：表7－1博特的需求表价格需求量大于7美元07～5美元15～3美元23～1美元31美元以下4B．如果一瓶水的价格是4美元，Bert会买多少瓶水？Bert从他的购买中得到了多少消费者剩余？在你的图形中标出Bert的消费者剩余。
答：如果价格是4美元，博特买2瓶水。
他从购买中得到了4美元的消费者剩余。
如图7－5所示，博特的消费者剩余是4美元(7－4+5－4＝4)。
图7－5博特的消费者剩余C．如果价格下降到2美元，需求量会有何变化？Bert的消费者剩余会有何变化？用你的图形说明这些变化。
答：如果价格下降到2美元，需求量增加到3，博特的消费者剩余增加到9美元。
如图7—6所示，博特的消费者剩余增加到9美元(7－2+5－2+3－2＝9)。
图7－6博特的消费者剩余5．Ernie有一台抽水机。
由于抽大量的水比抽少量的水困难，随着抽的水越来越多，生产一瓶水的成本增加。
下面是他生产每瓶水的成本：第一瓶水的成本1美元第二瓶水的成本3美元第三瓶水的成本5美元第四瓶水的成本7美元A．根据以上信息推导出Ernie的供给表。
画出他的瓶装水的供给曲线。
答：表7－2艾尼的供给表价格供给量7美元或以上45～7美元33～5美元21～3美元11美元以下0B ．如果一瓶水的价格是4美元，Ernie 会生产并销售多少瓶水？Ernie 从这种销售中得到多少生产者剩余？在你的图形中标出Ernie 的生产者剩余。
答：如果一瓶水的价格是4美元，艾尼生产并销售2瓶水。
艾尼的生产者剩余是4美元，如图7－8所示。
图7—8艾尼的生产者剩余C ．如果价格上升为6美元，供给量会有什么变化？Ernie 的生产者剩余会有何变化？在你的图形中标出这些变化。
答：如果价格上升为6美元，供给量会上升，艾尼的生产者剩余也上升。
如图7－9所示，供给量上升为3瓶，生产者剩余上升为9美元。
图7—9艾尼的生产者剩余6．考虑一个由问题4中的Bert 作为买者、问题5中的Ernie 作为卖者组成的市场。
A ．用Ernie 的供给表和Bert 的需求表找出价格为2美元、4美元和6美元时的供给量和需求量。
这些价格中哪一种能使供求达到平衡?答：这些价格中4美元一瓶时可使供求均衡。
表7－3供求表B ．在这种均衡时，消费者剩余、生产者剩余和总剩余是多少?答：在这种均衡中，消费者剩余是4美元，生产者剩余是4美元，总剩余是8美元。
C ．如果Ernie 少生产并且Bert 少消费一瓶水，总剩余会发生什么变动?答：总剩余会下降，变成6美元，因为市场并没有达到有效规模。
D ．如果Ernie 多生产并且Bert 多消费一瓶水，总剩余会发生什么变动?答：总剩余会下降，变成6美元，因为资源没有有效配置。
7．在过去几十年间，生产平面电视的成本降低了。
我们考虑这一事实的某些含义。
A ．用供求图说明生产成本下降对平面电视的价格和销售量的影响。
答：成本下降使供给曲线从S 1向右下方移动到S 2，立体声音响系统价格从P 1下降到P 2，销售量从Q 1上升到Q 2。
价格供给量需求量213422631图7－10平面电视供求图B．用你的图形说明消费者剩余和生产者剩余发生了什么变化?答：从图中可以看出，成本下降使消费者剩余增加，从面积AP1E1增加到面积AP1E2。
生产者剩余也增加了，从面积B1P1E1增加到面积B2P2E2。
C．假定平面电视的供给是非常富有弹性的。
谁从生产成本下降中获益最大？是平面电视的消费者还是生产者?答：假定平面电视的供给非常富有弹性，那么，消费者从生产成本下降中获益最大。
8．有四位消费者愿意为理发支付下列价格：Terry：7美元；Oprah：2美元；Ellen：8美元；Phil：5美元；有四家理发店，其成本如下：A企业：3美元B企业：6美元C企业：4美元D企业：2美元每家店只能为一个人理发。
从效率来看，应该有多少次理发？哪些店应该理发？哪些消费者应该理发？最大可能的总剩余是多少?答：从效率来看，应该有3次理发。
A、C、D理发店应理发，Terry、Ellen和Phil应该理发。
Oprah愿意支付的价格太低而企业B的成本太高，所以不会参与。
最大可能总剩余是11美元(8－2+7－3+5－4＝11)。
9．假设技术进步使生产电脑成本降低。
A．用供求图说明电脑市场上价格、数量、消费者剩余和生产者剩余会发生什么变动?答：成本下降使供给曲线从S1向右下方移动到S2，电脑市场上价格从P1下降到P2，销售量从Q1上升到Q2。
消费者剩余从面积AP1E1增加到AP2E2，生产者剩余从面积P1E1B1增加到P2E2B2。
图7－11电脑市场供求图B．电脑和加法机是替代品。
用供求图说明加法机市场上的价格、数量、消费者剩余和生产者剩余会发生什么变动？电脑技术进步对加法机生产者而言是好事还是坏事?答：由于电脑和加法机是替代品，电脑的销售量增加引起加法机的需求减少，需求曲线从D1向左下方移动到D2，价格从P1下降到P2，销售量从Q1下降到Q2。
生产者剩余从面积BP1E1减少到面积BP2E2，消费者剩余从面积A1P1E l减少到面积A2P2E2。
加法机生产者对电脑技术进步感到不幸。
图7－12加法机市场供求图C．电脑和软件是互补品。
用供求图说明软件市场上的价格、数量、消费者剩余和生产者剩余会发生什么变动?电脑技术进步对软件生产者而言是好事还是坏事?答：由于电脑和软件是互补品，电脑的销售量增加引起软件的需求减少，需求曲线从D1向右上方移动到D2，价格从P1上升到P2，销售量从Q1上升到Q2。
生产者剩余从面积BP1E1增加到面积BP2E2，消费者剩余从面积A1P I E l增加到面积A2P2E2。
软件生产者对电脑技术进步感到幸福。
D．上述分析有助于解释为什么软件生产者比尔·盖茨是世界上最富有的人之一吗?答：这种分析有助于解释软件生产者比尔·盖茨是世界上最富有的人之一。
电脑制造成本下降使电脑价格下降，人们对电脑的购买量不断上升。
没有软件，电脑只是一架空壳。
电脑销售量的快速增长必然带来软件业的繁荣，软件开发商的生产者剩余不断增加，比尔·盖茨的个人财富也会随之增加。
图7－13软件市场供求图10．考虑医疗保险如何影响所进行的医疗服务量。
假设一般的就医治疗成本为100美元，但一个有医疗保险的人只需自付20美元。
他的保险公司支付剩下的80美元。
(保险公司将通过保险费来收回这80美元，但一个人所支付的保险费不取决于他接受多少治疗。
)A．画出医疗市场上的需求曲线（在你的图形中，横轴应该代表治疗的次数）。
标出如果治疗价格为100美元，治疗的需求量。
答：我认为，100美元可以看做医疗市场达到均衡时的价格。
此时，治疗的需求量是Q1人，如图7－14。
图7－14医疗市场供给图B．在你的图上标出如果消费者每次治疗只支付20美元，治疗的需求量。
如果每次治疗的社会成本是实际的100美元，而且，如果个人有以上所述的医疗保险，这一治疗数量能使总剩余最大化吗？解释原因。
