📚 AP Microeconomics Practice Exam: Questions & Solutions | AP微观经济学真题练习与解析
Working through practice questions is one of the most effective ways to master the concepts tested on the AP Microeconomics exam. This article provides a set of original, exam-style multiple-choice and free-response questions covering every major unit of the course, followed by detailed, bilingual explanations. Whether you are reviewing for a unit test or preparing for the AP exam, these questions and step-by-step solutions will help you identify your strengths and target areas for improvement.
练习真题是掌握AP微观经济学考试概念的最有效方法之一。本文提供了一套原创的、考试风格的选择题和自由回答题，覆盖课程每个主要单元，并附有详细的中英双语解析。无论你是在为单元测验复习，还是为AP考试做准备，这些题目和逐步解析都能帮助你发现优势，并针对薄弱环节进行提高。
1. Scarcity and Opportunity Cost | 稀缺与机会成本
Question: The fundamental concept of scarcity in economics implies that
问题：经济学中稀缺性这一基本概念意味着
(A) resources are unlimited, but human wants are limited. (B) resources are limited, and human wants are unlimited. (C) governments must allocate all resources centrally. (D) scarcity only exists in developing countries. (E) opportunity cost is always zero.
(A) 资源是无限的，但人类欲望是有限的。(B) 资源是有限的，而人类欲望是无限的。(C) 政府必须集中分配所有资源。(D) 稀缺性只存在于发展中国家。(E) 机会成本始终为零。
Answer: (B). Scarcity is the condition that arises because resources are finite while human wants are virtually unlimited, forcing individuals and societies to make choices. Opportunity cost is a direct consequence of scarcity, as every decision incurs a trade-off.
答案：(B)。稀缺性是指资源有限而人类欲望无限的情况，这迫使个人和社会做出选择。机会成本是稀缺性的直接结果，因为每项决策都涉及权衡。
2. Production Possibilities Curve | 生产可能性曲线
Question: A country can produce the following combinations of food and clothing:
问题：一个国家可以生产以下的食品和服装组合：
| Combination | Food (units) | Clothing (units) |
|---|---|---|
| A | 100 | 0 |
| B | 80 | 20 |
| C | 50 | 40 |
| D | 0 | 50 |
What is the opportunity cost of moving from combination B to combination C?
从组合B移动到组合C的机会成本是多少？
Answer: Moving from B to C means clothing increases from 20 to 40 units (a gain of 20 units), while food drops from 80 to 50 units (a loss of 30 units). The opportunity cost of producing 20 additional units of clothing is the 30 units of food sacrificed.
答案：从B到C意味着服装从20增加到40单位（增加20单位），而食品从80下降到50单位（减少30单位）。生产额外20单位服装的机会成本是放弃的30单位食品。
Per-unit opportunity cost = 30 food / 20 clothing = 1.5 units of food per unit of clothing.
每单位机会成本 = 30食品 / 20服装 = 每单位服装1.5单位食品。
3. Comparative Advantage and Trade | 比较优势与贸易
Question: Worker A can produce 10 pies or 20 cakes in a day. Worker B can produce 15 pies or 45 cakes in a day. Who has the comparative advantage in cakes?
问题：工人A一天可以生产10个派或20个蛋糕。工人B一天可以生产15个派或45个蛋糕。谁在蛋糕上具有比较优势？
Solution: For Worker A, the opportunity cost of 1 cake = 10 pies / 20 cakes = 0.5 pie. For Worker B, the opportunity cost of 1 cake = 15 pies / 45 cakes = 1/3 pie (≈0.33 pie). Worker B has a lower opportunity cost for cakes, so B has the comparative advantage in cakes.
解答：工人A，1个蛋糕的机会成本 = 10派 / 20蛋糕 = 0.5个派。工人B，1个蛋糕的机会成本 = 15派 / 45蛋糕 = 1/3个派（≈0.33个派）。工人B生产蛋糕的机会成本更低，因此B在蛋糕上具有比较优势。
Note that Worker A has the comparative advantage in pies because 1 pie costs 2 cakes for A but 3 cakes for B.
注意，工人A在派上具有比较优势，因为A生产1个派的机会成本是2个蛋糕，而B是3个蛋糕。
4. Demand, Supply, and Market Equilibrium | 需求、供给与市场均衡
Question: Assume that coffee and tea are substitutes. If the price of coffee beans rises sharply due to a poor harvest, what will happen in the market for tea?
问题：假定咖啡和茶是替代品。如果由于歉收导致咖啡豆价格急剧上涨，茶叶市场会发生什么变化？
Answer: The higher price of coffee beans will shift the supply curve for coffee to the left, raising the price of coffee. As coffee becomes more expensive, consumers will switch to tea, increasing the demand for tea. This causes the demand curve for tea to shift to the right, leading to a higher equilibrium price and a higher equilibrium quantity for tea.
答案：咖啡豆价格上涨会使咖啡的供给曲线向左移动，从而提高咖啡价格。随着咖啡变贵，消费者会转向茶，增加了对茶的需求。这导致茶的需求曲线向右移动，带来更高的均衡价格和更高的均衡数量。
5. Price Elasticity of Demand | 需求价格弹性
Question: When the price of a good rises from $8 to $12, the quantity demanded falls from 40 to 30 units. Using the midpoint method, calculate the price elasticity of demand. Is demand elastic, unit elastic, or inelastic?
问题：当一种商品的价格从8美元上涨到12美元，需求量从40单位下降到30单位。使用中点法计算需求价格弹性。需求是富有弹性、单位弹性还是缺乏弹性？
Ed = | (Q₂ − Q₁) / [(Q₁ + Q₂)/2] ÷ (P₂ − P₁) / [(P₁ + P₂)/2] |
Solution: Q₁ = 40, Q₂ = 30, P₁ = 8, P₂ = 12. Average quantity = (40+30)/2 = 35; change in quantity = −10. Average price = (8+12)/2 = 10; change in price = 4.
解答：Q₁ = 40, Q₂ = 30, P₁ = 8, P₂ = 12。平均数量 = 35，数量变动 = −10；平均价格 = 10，价格变动 = 4。
Ed = | (−10/35) / (4/10) | = | −0.2857 / 0.4 | ≈ 0.714
Since the absolute value of elasticity is less than 1, demand is inelastic.
由于弹性绝对值小于1，需求缺乏弹性。
6. Consumer Surplus, Producer Surplus, and Efficiency | 消费者剩余、生产者剩余与效率
Question: The demand for a good is given by P = 14 − Q, and the supply is given by P = 2 + Q. Find the equilibrium price, quantity, consumer surplus (CS), and producer surplus (PS). Then, if a $2 per-unit tax is imposed on producers, calculate the new deadweight loss.
问题：某种商品的需求为P = 14 − Q，供给为P = 2 + Q。求均衡价格、数量、消费者剩余(CS)和生产者剩余(PS)。然后，如果对生产者征收每单位2美元的税，计算新的无谓损失。
Equilibrium: 14 − Q = 2 + Q ⇒ 2Q = 12 ⇒ Q* = 6, P* = 14 − 6 = 8. CS = ½ × (14 − 8) × 6 = 18. PS = ½ × (8 − 2) × 6 = 18. Total surplus = 36.
均衡：14 − Q = 2 + Q ⇒ 2Q = 12 ⇒ Q* = 6，P* = 8。CS = ½×(14−8)×6 = 18。PS = ½×(8−2)×6 = 18。总剩余 = 36。
With a $2 tax, the new supply is P = 4 + Q. New equilibrium: 14 − Q = 4 + Q ⇒ Q’ = 5. Buyers pay PD = 14 − 5 = 9, sellers receive PS = 4 + 5 = 6 (or 9 − 2 = 6). Deadweight loss = ½ × (2) × (6 − 5) = 1.
征收2美元税后，新供给为P = 4 + Q。新均衡：14 − Q = 4 + Q ⇒ Q’ = 5。买方支付PD = 9，卖方得到PS = 6（或9−2=6）。无谓损失 = ½ × 2 × (6−5) = 1。
7. Price Ceilings and Price Floors | 价格上限与价格下限
Question: In a rental market, demand is QD = 100 − 2P and supply is QS = 3P. The government sets a price ceiling of $15. Determine the shortage or surplus caused by this policy.
问题：在租赁市场中，需求为QD = 100 − 2P，供给为QS = 3P。政府设定价格上限为15美元。计算该政策导致的短缺或过剩。
Equilibrium without control: 100 − 2P = 3P ⇒ 5P = 100 ⇒ P* = 20, Q* = 60. At a ceiling of $15 (below equilibrium), QD = 100 − 2×15 = 70, QS = 3×15 = 45. Shortage = 70 − 45 = 25 units.
无管制均衡：100 − 2P = 3P ⇒ P* = 20，Q* = 60。在15美元的价格上限下（低于均衡），需求量 = 100 − 30 = 70，供给量 = 45。短缺 = 70 − 45 = 25单位。
This binding price ceiling creates a persistent shortage, which may lead to black markets or reduced quality.
这一有效的价格上限造成了持续短缺，可能导致黑市或质量下降。
8. Perfect Competition | 完全竞争
Question: A perfectly competitive firm’s total cost is TC = 50 + 2q + q², and the market price is $14. What is the profit-maximizing output? Calculate the firm’s profit or loss at that output.
问题：一家完全竞争企业的总成本为TC = 50 + 2q + q²，市场价格为14美元。利润最大化产量是多少？计算在该产量下企业的利润或亏损。
In perfect competition, P = MC. MC = dTC/dq = 2 + 2q. Set MC = 14 ⇒ 2 + 2q = 14 ⇒ 2q = 12 ⇒ q = 6. Total revenue = 14 × 6 = 84. Total cost = 50 + 2×6 + 6² = 50 + 12 + 36 = 98. Profit = 84 − 98 = −14, a loss of $14.
完全竞争下，P = MC。MC = dTC/dq = 2 + 2q。令MC = 14 ⇒ q = 6。总收入 = 84，总成本 = 98。利润 = −14美元，亏损14美元。
Since price is above AVC (at q=6, AVC = variable cost/q = (2×6+36)/6 = 48/6 = 8), the firm will continue to produce in the short run.
由于价格高于平均可变成本（q=6时，AVC = 48/6 = 8），企业在短期会继续生产。
9. Monopoly | 垄断
Question: A monopolist faces inverse demand P = 20 − Q and has a total cost function TC = 5 + 2Q². Determine the profit-maximizing quantity and price, and compute the monopoly profit.
问题：垄断者面临反需求函数P = 20 − Q，总成本为TC = 5 + 2Q²。求利润最大化的数量和价格，并计算垄断利润。
Total revenue TR = P×Q = 20Q − Q², so MR = 20 − 2Q. Marginal cost MC = dTC/dQ = 4Q. Set MR = MC: 20 − 2Q = 4Q ⇒ 20 = 6Q ⇒ Q = 10/3 ≈ 3.33. Price P = 20 − 10/3 = 50/3 ≈ 16.67.
总收入TR = 20Q − Q²，边际收益MR = 20 − 2Q。边际成本MC = 4Q。令MR=MC：20−2Q=4Q ⇒ Q=10/3≈3.33。价格P=20−10/3=50/3≈16.67。
Profit = TR − TC = (20×(10/3) − (10/3)²) − (5 + 2×(10/3)²) = (200/3 − 100/9) − (5 + 200/9) = (600/9 − 100/9) − (45/9 + 200/9) = 500/9 − 245/9 = 255/9 ≈ 28.33.
利润 = 总收入 − 总成本 = 255/9 ≈ 28.33。
10. Oligopoly and Game Theory | 寡头与博弈论
Question: Two firms, A and B, must decide whether to advertise. The payoff matrix is shown below (profits in millions):
问题：两家企业A和B必须决定是否做广告。收益矩阵如下（利润单位为百万美元）：
| Firm B: Advertise | Firm B: Don’t Advertise | |
|---|---|---|
| Firm A: Advertise | (5, 5) | (12, 3) |
| Firm A: Don’t Advertise | (3, 12) | (8, 8) |
Find the dominant strategy for each firm, if any, and identify the Nash equilibrium.
找出每家企业的占优策略（如果有），并确定纳什均衡。
For Firm A: If B chooses Advertise, A gets 5 by advertising and 3 by not → A prefers Advertise. If B chooses Don’t Advertise, A gets 12 by advertising and 8 by not → A prefers Advertise. So advertising is a dominant strategy for A. Similarly, for Firm B, advertising is a dominant strategy. Therefore, (Advertise, Advertise) is the unique Nash equilibrium, yielding (5,5).
对A：如果B选择做广告，A做广告得5，不做得3 → A偏向做广告。如果B不做广告，A做广告得12，不做得8 → A偏向做广告。因此做广告是A的占优策略。同样，B的占优策略也是做广告。所以（做广告，做广告）是唯一的纳什均衡，收益为(5,5)。
11. Factor Markets: Labor | 要素市场：劳动力
Question: A firm hires labor in a perfectly competitive labor market. The wage rate is $25 per hour. The firm’s marginal product of labor (MPL) schedule is shown:
问题：一家企业在完全竞争的劳动力市场上雇佣工人。工资率为每小时25美元。企业的劳动边际产出(MPL)表如下：
| Labor (workers) | MPL (units per hour) | Price of output |
|---|---|---|
| 1 | 10 | $4 |
| 2 | 8 | $4 |
| 3 | 6 | $4 |
| 4 | 4 | $4 |
How many workers will the firm hire to maximize profit?
企业会雇佣多少工人以实现利润最大化？
The firm hires until marginal revenue product of labor (MRPL) equals the wage. MRPL = MPL × price. For the 1st worker: MRPL = 10×4 = 40 > 25; 2nd: 8×4 = 32 > 25; 3rd: 6×4 = 24 < 25. So the 3rd worker would add $24 in revenue, which is less than the $25 wage. The firm should hire 2 workers.
企业雇佣工人直到劳动的边际收益产品(MRPL)等于工资。MRPL = MPL × 产品价格。第一个工人：MRPL=40>25；第二个：32>25；第三个：24<25。因此第三个工人带来的收入为24美元，低于25美元的工资，企业应雇佣2个工人。
12. Externalities and Market Failure | 外部性与市场失灵
Question: A factory’s production generates air pollution that harms nearby residents. The private marginal cost of production is PMC = 10 + Q, and the external cost is constant at $4 per unit. Demand is given by P = 22 − Q. Find the socially optimal quantity and the deadweight loss if the externality is not corrected.
问题：一家工厂的生产造成空气污染，损害附近居民。生产的私人边际成本为PMC = 10 + Q，外部成本恒为每单位4美元。需求为P = 22 − Q。求社会最优产量以及如果不纠正外部性时的无谓损失。
Social marginal cost SMC = PMC + external cost = 14 + Q. Socially optimal: 22 − Q = 14 + Q ⇒ 2Q = 8 ⇒ Qs = 4, Ps = 18. Private optimum (market outcome): 22 − Q = 10 + Q ⇒ 2Q = 12 ⇒ Qp = 6, Pp = 16. Deadweight loss = area between SMC and demand from Qs to Qp. At Q=6, SMC = 20, while the demand value is 16. DWL = ½ × (6 − 4) × (20 − 16) = ½ × 2 × 4 = 4.
社会边际成本SMC = PMC + 外部成本 = 14 + Q。社会最优：22−Q = 14+Q ⇒ Qs=4，Ps=18。私人最优（市场结果）：22−Q = 10+Q ⇒ Qp=6，Pp=16。无谓损失为SMC与需求曲线之间从Qs到Qp的面积。在Q=6时，SMC=20，需求价值为16。DWL = ½×(6−4)×(20−16)=4。
A corrective tax of $4 per unit would shift PMC to SMC, eliminating the DWL.
每单位4美元的矫正税会使PMC移至SMC，消除无谓损失。
Published by TutorHao | AP Microeconomics Revision Series | aleveler.com
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