期中考试题2_经原(2016秋)答案_97760860

经济学原理I （2016年秋季学期）

期中考试2（A 卷答案）

（2016/11/30）

（所有题目答案需写在另发的答题本上，否则无效。本试卷满分50分。）

1. 判断以下陈述是否正确，阐述理由。必要时画出图形。（4分*3题=12分）

1.1 农业丰收可能既降低了农民的总收益，又降低了农民的总剩余。（提示：考虑供给弹性。） 正确。如下图。考虑极端情形，即农产品供给完全无弹性。则总剩余与总收益的变动是相同的（从面积P 1E 1Q 1O 下降到P 2E 2Q 2O ）。当农产品需求缺乏弹性时，二者都是下降的。

1.2 A tax that has no deadweight loss cannot raise any revenue for the government, while a tax

that raises no revenue for the government cannot have any deadweight loss.

False.A tax when either supply or demand is perfectly inelastichas neither an effect on quantity nor any deadweight loss, but it does raise revenue. A 100% tax imposed on sellers will raise no revenue, yet it has a large deadweight loss, because it reduces the quantity sold to zero.

1.3 Suppose that the government decides to issue tradable permits for certain form of pollution.

It does not matter for economic efficiency whether the government distributes or auctions the permits, and if the government chooses to distribute the permits, how the government allocates permits among firms.

True.In terms of economic efficiency in the market for pollution, it does not matter if the government distributes the permits or auctions them off, or how the government allocated the permits to firms,as long as firms can sell the permits to each other. The permits would end up in the hands of the firms who value them most highly. Thus, the allocation of permits among firms would not matter for efficiency.

2. 选择题。每个题目只有一个正确答案。（2分*4题=8分）

2.1 John has been working as a tutor for $300 a semester. When the university raises the price it pays tutors to $400, Emily enters the market and begins tutoring as well. As a result of this price increase, producer surplus for John rises by ; producer surplus for Emily rises by ; and

total

P Q

P 112P 2O

producer surplus rises by .

A.$100; $100; $200

B.$100; less than $100; between $100 and $200

C.$100; more than $100; between $200 and $300

D.less than $100; less than $100; between $100 and $200

2.2 Eggs have a supply curve that is linear and upward-sloping and a demand curve that is linear and downward sloping. If a 2 cent per egg tax is increased to 3 cents, then:

A.both the deadweight loss of the tax and the government’s tax revenue increase by less than

50 percent.

B.both the deadweight loss of the tax and the government’s tax revenue increase by more than

50 percent.

C.the deadweight loss of the tax increases by mo re than 50 percent, and the government’s tax

revenue increases by less than 50 percent.

D.the deadweight loss of the tax increases by less than 50 percent, and the government’s tax

revenue increases by more than 50 percent.

2.3 If the tax code exempts the first $20,000 of income from taxation and then taxes 25 percent of all income above that level, then a person wo earns $50,000 has an average tax rate of percent and a marginal tax rate of percent.

A.15, 25

B.25, 15

C.25, 30

D.30, 25

2.4 累退税是随着个人收入（以I表示）的上升，平均税率（以t(I)表示）下降的一种税收制度。假定累退税的税收收入（以T表示）随着收入的增加仍然是上升的，即符合纵向平等原则。此外，税收收入不得大于个人收入。则以下各个平均税率的表达式中，符合上述所有原则的是（假定I 1）：

A.t(I)=a，a为常数，0

B.t(I)=I-a，a为常数，0

C.t(I)=a*I-1，a为常数，a>0。

D.不存在这样的平均税率

3.两部分定价（8分）

某游乐场里有多个游乐项目，一个典型消费者对于游乐场项目的需求曲线为Q=10-5P，其中P为该游乐场对于每个游乐项目的定价（元），假定每个项目的定价相同。Q为在该定价下，典型消费者对于游乐项目的需求数量（个）。假定游乐场提供游乐项目的成本是零。（1）画出一个典型消费者的需求曲线。（1分）

如下图。