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Intermediate Microeconomics: A Tool-Building Approach

Samiran Banerjee

Chapter 14

Externalities - all with Video Answers

Educators


Chapter Questions

Problem 1

There are two consumers, $a$ and $b$, in an economy with two goods $x$ and $y$, and an initial endowment $\omega=((0,1),(1,0))$. The utility functions of the consumers are
$$
\begin{aligned}
u^a\left(x^a, y^a, x^b\right) & =x^a+1.5 y^a+0.5 x^b \\
u^b\left(x^b, y^b\right) & =x^b y^b
\end{aligned}
$$
They each choose their consumption levels of the goods independently but $b^{\prime}$ s consumption of the $x$ good confers a positive externality on $a$.
(a) Find the contract curve for this two-person Edgeworth box.
(b) Find a Walras equilibrium. Is it Pareto efficient? Explain why or why not.

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Problem 2

Romeo and Juliet are the only two consumers in an economy with two goods $x$ and $y$, and Romeo's endowment is $\omega^R=(0,1)$ while Juliet's is $\omega^I=(1,0)$. They each choose their consumption levels of the goods independently. But because they are madly in love, they get satisfaction not only from their own consumption of the goods but also from the other's consumption of both goods:
$$
\begin{gathered}
u^R\left(x^R, y^R, x^I, y^I\right)=x^R y^R+x^I+y^J, \\
u^J\left(x^R, y^R, x^J, y^J\right)=x^J y^I+x^R+y^R .
\end{gathered}
$$
(a) Find the contract curve for this two-person Edgeworth box.
(b) Find a Walras equilibrium. Is it Pareto efficient? Explain why or why not.

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04:56

Problem 3

In the production externality example from section 14.1 .2 , suppose the firms are producing $a^*=18$ and $f^*=15$ units under free market conditions. Consider two alternative property rights regimes.
(a) Suppose the upstream acid firm is liable for the damage it causes to the downstream fishery: it has to compensate the fishery af. Calculate how many units of acid $(\bar{a})$ and fish $(\bar{f})$ will be produced and the firm profits, $\bar{\pi}^A$ and $\bar{\pi}^F$.
(b) Suppose the upstream acid firm is not liable for the damage it causes to the downstream fishery. The fishery is willing to pay a bribe of $b$ dollars to the acid producer for cutting back the production of acid to the Pareto efficient level of $a^{\circ}=8$ units. What is the minimum bribe, $b_{\min }$ that firm $A$ will be willing to accept? What is the maximum bribe, $b_{\max }$, that firm $F$ is willing to pay?
(c) Does the Coase "theorem" hold here? Explain why or why not.

EA
Erwin Antoni
Numerade Educator

Problem 4

An economy consists of two consumers, labeled $a$ and $b$. There are two commodities, $x$ and $y$, that can be traded. Good $x$ is food and is desired by each consumer. However, $y$ is a good for person $a$ but a "bad" for person $b$. We interpret $y^a$ as the level of smoke consumed by person $a$, while $y^b=1-y^a$ is the level of remaining clean air consumed by $b$. The utility functions and demands of each consumer is given in the table below:
In the table, $m^a$ and $m^b$ refer to the value of each consumer's endowment. The price of $y$ (for the right to smoke or clean air) is normalized to $$\$ 1$$; for simplicity, write $p_x$ as just $p$.
(a) Suppose $\omega=((3,0),(3,1))$. Draw the set of interior Pareto efficient allocations in an Edgeworth box for this economy.
(b) Suppose $\omega=((3,0),(3,1))$. We interpret this initial endowment to be the case where person $a$ does not have the right to smoke, i.e., person $b$ has the right to clean air. Suppose $a$ and $b$ can trade food for the right to smoke. Find the Walras equilibrium price of $x, \tilde{p}$, for this economy and the Walras allocation $\left(\left(\tilde{x}^a, \tilde{y}^a\right),\left(\tilde{x}^b, \tilde{y}^b\right)\right)$. Draw the Walras budget and Walras allocation in the Edgeworth box.
(c) Suppose $\omega^{\prime}=((3,1),(3,0))$. We interpret this initial endowment to be the case where person $a$ does have the right to smoke, i.e., person $b$ does not have the right to clean air. Suppose $a$ and $b$ can trade food for the right to smoke. Find the Walras equilibrium price of $x, \hat{p}$, for this economy and the Walras allocation $\left(\left(\hat{x}^a, \hat{y}^a\right),\left(\hat{x}^b, \hat{y}^b\right)\right)$. Draw the Walras budget and Walras allocation in the Edgeworth box.
(d) Does the Coase "theorem" hold here? Explain why or why not.

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Problem 5

An economy consists of two consumers, labeled $a$ and $b$. There are two commodities, $x$ and $y$, that can be traded. Good $x$ is food and is desired by each consumer. However, $y$ is a good for person $a$ but a "bad" for person $b$. We interpret $y^a$ as the level of smoke consumed by person $a$, while $y^b=1-y^a$ is the level of remaining clean air consumed by $b$. The utility functions and demands of each consumer is given in the table below:
In the table, $m^a$ and $m^b$ refer to the value of each consumer's endowment. The price of $y$ (for the right to smoke or clean air) is normalized to $$\$ 1$$; for simplicity, write $p_x$ as just $p$.
(a) Suppose $\omega=((4,0),(4,1))$. We interpret this initial endowment to be the case where person $a$ does not have the right to smoke, i.e., person $b$ has the right to clean air. Suppose $a$ and $b$ can trade food for the right to smoke. Find the Walras equilibrium price of $x, \tilde{p}$, for this economy and the Walras allocation $\left(\left(\tilde{x}^a, \tilde{y}^a\right),\left(\tilde{x}^b, \tilde{y}^b\right)\right)$. Is this Walras allocation Pareto efficient?
(b) Suppose $\omega=((4,1),(4,0))$. We interpret this initial endowment to be the case where person $a$ does have the right to smoke, i.e., person $b$ does not have the right to clean air. Suppose $a$ and $b$ can trade food for the right to smoke. Find the Walras equilibrium price of $x, \hat{p}$, for this economy and the Walras allocation $\left(\left(\hat{x}^a, \hat{y}^a\right),\left(\hat{x}^b, \hat{y}^b\right)\right)$. Is this Walras allocation Pareto efficient?
(c) Does the Coase "theorem" hold here? Explain why or why not.

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02:14

Problem 6

Three firms put 4 tons of noxious gases into the atmosphere each in a year. The total abatement costs for each firm are
$$
\begin{aligned}
& T A C_1=5 e_1^2, \\
& T A C_2=10 e_2+5 e_2^2, \\
& T A C_3=20 e_3+5 e_3^2,
\end{aligned}
$$
where $e_i$ is the amount of the gas emitted by firm $i$.
(a) Suppose the government wants to cut the total emissions from 12 units to 6 units by direct regulation, requiring each firm to cut back on two units of emission each. How much will this plan cost overall?
(b) Suppose the government wants to cut the total emissions from 12 units to 6 units. What is the socially efficient (i.e., that costs the least to society) way to cut back on emissions? How much will each firm cut back in this case?
(c) Suppose the government wants to cut the total emissions from 12 units to 6 units using an emissions tax. What level of tax will bring this about? How much will the tax revenue collected be?

Nick Johnson
Nick Johnson
Numerade Educator