爱华网复习题：
1. What is the relationship between a firm’s total revenue,profit, and total cost? 企业总收益、利润和总成本之间的关系。
答：利润=企业总收益-总成本
2. Give an example of an opportunity cost that an accountantmight not count as a cost. Why would the accountant ignore thiscost? 举例说明会计不算作成本的机会成本。为何会计忽略这个成本？
答：私人业主如果不给自己开工资，那么他劳动的机会成本没有算作企业成本。因为没有现金流发生，所以会计忽略了这个成本。
3. What is marginal product, and what does it mean if it isdiminishing? 什么是边际产量，边际产量递减，意味着什么？
答：额外增加一份投入而导致的多产出量。边际产量递减，是指一种投入的边际产量，随着投入增加而减少的情况。
4. Draw a production function that exhibits diminishing marginalproduct of labor. Draw the associated total cost curve. (In bothcases, be sure to label the axes.) Explain the shapes of the twocurves you have drawn.绘出表示劳动这种投入的力生产函数，说明其边际产量递减。画出相关的总成本曲线（两种情况都标出坐标轴）。解释这两条曲线的形状。
答：
斜率递减。
斜率递增
5. Define total cost, average total cost, and marginal cost. Howare they related? 定义总成本，平均总成本，边际成本。它们之间关系是什么？
答：生产一定量产品需要所有投入的成本，包括固定成本和可变成本。
平均成本是有代表意义的一单位产品的成本，等于总成本除以产量。
边际成本是多生产一单位产品，需要增加的成本。它等于成本总成本增加量除以产量增加量。
它们之间另外一种关系则是，当边际成本大于平均总成本时，平均总成本是上升的。当边际成本小于平均总成本时，平均总成本是下降的。
6. Draw the marginal-cost and average-total-cost curves for atypical firm. Explain why the curves have the shapes that they doand why they cross where they do.绘出一家典型企业的边际成本和平均总成本曲线。解释其形状和交点。
答：
主要有以下特征：（1）除了开始极低产量范围，其它产量范围内，边际成本随产量增加而增加。（2）平均总成本则是U形曲线，开始随产量增加而减少，达到一定产量后，平均总成本开始随产量增加而增加。（3）边际成本曲线总是相交于平均总成本曲线的拐点。
7. How and why does a firm’s average-total-cost curve differ in theshort run and in the long run? 为何一个企业的短期平均总成本和长期平均总成本不一致？
答：长期平均总成本总是比短期平均总成本低。长期考量，企业可以如果提高产量，可以有时间优化生产要素投入配置，从而使边际成本递增不太“陡峭”。
8. Define economies of scale and explain why they might arise.Define diseconomies of scale and explain why theymight arise. 给规模经济下定义，解释为何会产生规模经济。给规模不经济下定义，解释为何产生规模不经济。
答：随着产量增加，长期平均总成本下降，则存在规模经济。因为工人的专业化。
随着产量增加，长期平均总成本上升，则存在规模不经济。因为，企业大型化后，内部协调困难。
应用题：
1. This chapter discusses many types of costs: opportunity cost,total cost, fixed cost, variable cost, average total cost, andmarginal cost. Fill in the type of cost that best completes thephrases below: 本文讨论了很多成本，下面牵涉到什么成本。
a. The true cost of taking some action is its __机会成本_____.
b. _平均总成本______ is falling when marginal cost is below it, andrising when marginal cost is above it.
c. A cost that does not depend on the quantity produced is a__固定成本_____.
d. In the ice-cream industry in the short run, __可变成本_____ includesthe cost of cream and sugar, but not the cost of the factory.
e. Profits equal total revenue less ___总成本____.
f. The cost of producing an extra unit of output is_边际成本______.
2. Your aunt is thinking about opening a hardware store. Sheestimates that it would cost $500,000 per year to rent the locationand buy the stock. In addition, she would have to quit her $50,000per year job as anaccountant.你的婶子考虑开个杂货店，租门面和进货每年需要支付500，000元，另外她要辞去其年薪50，000元的工作。
a. Define opportunity cost.定义机会成本。
答：略。
b. What is your aunt’s opportunity cost of running a hardware storefor a year? If your aunt thought she could sell $510,000 worth ofmerchandise in a year,
should she open the store? Explain.
答：她的机会成本是500，000+50，000=550，000元。
550，000大于其总产出（还不是总利润），所以，她开这个门市经济上不合算。
3. Suppose that your college charges you separately for tuitionand for room and board.假设大学向你分别收取学费和食宿费。
a. What is a cost of attending college that is not an opportunitycost? 哪种成本不是上大学的机会成本？
答：食宿费，因为无论上不上大学，食宿费都要消费。
b. What is an explicit opportunity cost of attending college?上大学的显性机会成本是什么？
答：学费。
c. What is an implicit opportunity cost of attending college?上大学的隐性机会成本呢？
答：大学四年间，无法工作而减少的收入。
4. A commercial fisherman notices the following
relationship between hours spent fishing and the
quantity of fish caught:
HOURSQUANTITY OF FISH (IN POUNDS)
00
110
218
324
428
530
a. What is the marginal product ofeach hour spent fishing? 每小时的边际产量。
答：
b. Use these data to graph the fisherman’s production function.Explain its shape.生产函数和形状解释。
答：
可能是鱼塘鱼，越钓越少，越难钓。
c. The fisherman has a fixed cost of $10 (his pole). Theopportunity cost of his time is $5 per hour. Graph the fisherman’stotal-cost curve. Explain itsshape.固定成本鱼竿10元，他的时间机会成本是5元/小时。画出其总成本曲线，解释其形状。
答：
产量增加导致的成本增加不成比例。
5. Nimbus, Inc., makes brooms and then sells them doorto-door.Here is the relationship between the number of workers and Nimbus’soutput in a given day:尼姆巴斯公司生产扫帚，并挨门销售的公司。
a. Fill in the column of marginal products. What pattern do yousee? How might you explain it? 填写边际产量栏。解释。
答：先增后减。
b. A worker costs $100 a day, and the firm has fixed costs of $200.Use this information to fill in the column for total cost.每个工人每天工资100元，固定投资200元。填写总成本栏。
答：见上表。
c. Fill in the column for average total cost. (Recall that ATC =TC/Q.) What pattern do you see?
答：见上表，U型。
d. Now fill in the column for marginal cost. (Recall that MC =TC/Q.) What pattern do you see?
答：见上表。边际成本也是U形，但是上升更陡峭。
e. Compare the column for marginal product and the column formarginal cost. Explain the relationship.
答：边际产量上升时，边际成本下降。反之也然。
f. Compare the column for average total cost and the column formarginal cost. Explain the relationship.
答：当边际成本低于平均总成本时，平均总成本是下降的。当边际成本高于平均总成本后，平均总成本开始上升。
6. Suppose that you and your roommate have started a bageldelivery service on campus. List some of your fixed costs anddescribe why they are fixed. List some of your variable costs anddescribe why they arevariable.假设你和同学在校园递送百吉圈快餐。列出你的生意的固定成本和可变成本。
答：买自行车（汽车），印刷广告宣传单。
可变成本包括买百吉圈的钱和汽油费。
7. Consider the following cost information for a pizzeria:
Q(DOZENS) TOTALCOSTVARIABLE COST
0$300$ 0
135050
239090
3420120
4450150
5490190
6540240
a. What is the pizzeria’s fixed cost?
答：300
b. Construct a table in which you calculate the marginal cost perdozen pizzas using the information on total cost. Also calculatethe marginal cost per dozen pizzas using the information onvariable cost. What is the relationship between these sets ofnumbers? Comment.用总成本计算边际成本。用可变成本计算边际成本。之间关系。
答：总成本的变化，其实就是可变成本变化。
8. You are thinking about setting up a lemonade stand. The standitself costs $200. The ingredients for each cup of lemonade cost$0.50.你想开柠檬水店。店成本200元。每杯成本是0.5元。
a. What is your fixed cost of doing business? What is your variablecost per cup?
答：200元。0.5元。
b. Construct a table showing your total cost, average total cost,and marginal cost for output levels varying from zero to 10gallons. (Hint: There are 16
cups in a gallon.) Draw the three cost curves.
答：
9. Your cousin Vinnie owns a painting company with fixed costsof $200 and the following schedule for variable costs:
QUANTITYOF HOUSES
PAINTED PERMONTH
1234567
Variable costs $10 $20 $40 $80 $160 $320 $640
Calculate average fixed cost, average variable cost, and averagetotal cost for each quantity. What is the efficient scale of thepainting company? 平均固定成本，平均可变成本、平均总成本。油漆公司的有效规模是多少？
答：4座房子。
从图形上看，随着产量增加，平均可变成本增加，平均固定成本下降，升级相抵，有个最小值。即有效率的产量。
10. Healthy Harry’s Juice Bar has the following cost schedules:果汁店成本表。
Q(VATS)VARIABLECOSTTOTAL COST
0$0$ 30
11040
22555
34575
470100
5100130
6135165
a. Calculate average variable cost, average total cost, andmarginal cost for each quantity. 计算平均可变成本、平均总成本边际成本。
答:
b. Graph all three curves. What is the relationship between themarginal-cost curve and the averagetotal- cost curve? Between themarginal-cost curve
and the average-variable-cost curve? Explain.
答：产量小于4缸时，边际成本曲线在平均总成本曲线之下，大于4缸时，在其上。
边际成本曲线在平均可变成本曲线之上 。
11. Consider the following table of long-run total cost forthree different firms:
QUANTITY
1234567
Firm A$60 $70$80$90$100$110 $120
Firm B112439567596119
Firm C2134496685106129
Does each of these firms experience economies of scale ordiseconomies of scale?
答：
公司1有规模经济。公司2有规模不经济。公司3在产量从1-3有规模经济，大于3则有规模不经济。
其实就是，增加固定投资提高产量，会不会导致单位成本降低。
