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Department of Economics
University of Toronto
Prof. Gustavo Indart
February 6, 2009
SOLUTIONS
ECO 100Y
INTRODUCTION TO ECONOMICS
Midterm Test # 3
LAST NAME
FIRST NAME
STUDENT NUMBER
INSTRUCTIONS:
1.
2.
5.
The total time for this test is 1 hour and 50 minutes.
Aids allowed: a simple calculator.
Write with pen instead of pencil.
DO NOT WRITE IN THIS SPACE
Part I
1.
/14
2.
/12
3.
/12
4.
/12
Part II
/50
TOTAL
/100
Page 1 of 11
PART I
(50 marks)
Instructions: Answer all questions in the space provided.
1. Long-Run Competitive Equilibrium (14 marks)
Consider the hot dog street vendor industry in Piriapolis, a small city with the world’s greatest
consumption of hot dogs per capita. The city’s hot dog street vendor industry is a perfectly
competitive, constant cost industry. The industry consists of 100 identical street vendors. The
diagrams below provide information about the industry — short-run supply (S) and demand (D)
curves — and about a representative street vendor — short-run marginal cost (SRMC), shortrun average total cost (SRAC), and long-run average cost (LRAC).
S’’
Price (dollars)
S
LRS’
3.5
3.0
LRS
2.5
LRAC’
SRMC’
5.0
Price (dollars)
S’
5.0
SRMC
SRAC’
LRAC
SRAC
3.5
3.0
2.5
D
8 10
Hot dogs/day (thousands)
90
100
Hot dogs/day
a) What are the industry short-run equilibrium price and quantity? (1 mark) How many hot
dogs does each vendor sell in this short-run equilibrium? Briefly explain. (1 mark) Is each
vendor making economic profits or economic losses in this short-run equilibrium? Briefly
explain. (1 mark)
P=$
2.5
Industry quantity = 10,000
Vendor’s quantity =
100
Since the industry output is 10,000 hot dogs/day and there are 100 identical street vendors,
then each street vendor will sell 10,000/100 = 100 hot dogs per day.
Each street vendor is making the normal profits, i.e., zero economic profits, since P = SRAC
at the equilibrium level of output.
Page 2 of 11
b) Is the industry in long-run equilibrium? Briefly explain. (1 mark) Draw the industry long-run
supply (LRS) curve in the diagram above. (1 mark)
Yes, the industry is in long-run equilibrium because every firm is making zero economic
profits and producing with the optimum scale of production (i.e., at the minimum of the LRAC
curve).
c) Suppose now that the government introduces a specific tax of $1 per hot dog to be paid by
the street vendors. In the diagram above, show the short-run impact of this specific tax by
carefully re-drawing the affected curves. (2 marks)
d) What are the new industry short-run equilibrium price and quantity? How many hot dogs
does each vendor sell in this short-run equilibrium? (2 marks) Is each vendor making
economic profits or losses in this short-run equilibrium? Briefly explain. (1 mark)
P=$
3.00
Industry quantity = 9,000
Vendor’s quantity =
90
Each street vendor is making economic losses, since P < SRAC at the equilibrium level of
output.
e) In the diagram above, carefully draw the new long-run industry supply curve. (1 mark) What
are the new industry long-run equilibrium price and quantity? How many hot dogs does each
vendor sell in this new long-run equilibrium? (2 marks) How many vendors are there in the
new long-run equilibrium? Briefly explain. (1 mark)
P=$
3.50
Industry quantity =
8,000
Vendor’s quantity =
100
Since the industry output is 8,000 hot dogs/day and each vendor is selling 100 hot dogs per
day, the number of vendors is 8,000/100 = 80.
Page 3 of 11
2. Regulated Monopoly (12 marks)
Price of basic cable services (dollars/month)
Consider the monopoly firm providing cable services in your neighbourhood. The diagram below
shows the demand curve (D) for basic cable services, the firm’s marginal cost curve (MC), and
the firm’s average total cost curve (AC).
Economic
profits of
unregulated
monopolist
150
Deadweight
loss
AC’
MC
AC
110
100
90
80
50
D
10
14
20
30
Quantity of households/month (thousands)
a) If the government does not regulate this monopolist, which price will it charge? Show the
monopolist’s price and quantity in the diagram above. (2 marks) What economic profits or
losses will the monopolist make? Shade the area of economic profits or losses in the
diagram above. (2 marks) Illustrate the allocative inefficiency this creates by shading the
deadweight loss from monopoly. (2 marks)
PM = $
110
Profits (losses) = $
300,000
b) Suppose now that the government decides to regulate this monopolist in order to achieve
allocative efficiency, what price ceiling should the government impose? (1 mark) What
economic profits or losses will the monopolist make? Show your work. (2 marks)
PC = $
90
Profits (losses) = $
140,000
Economic profits = (PC – AC) Q = (90 – 80) 14 = 140 thousand.
Page 4 of 11
c) Suppose that in addition to achieving allocative efficiency the government also wants this
monopolist to make normal profits (i.e., zero economic profits). What type of tax or subsidy
should the government introduce? Briefly explain. (1 mark) What is the size of this tax or
subsidy? (1 mark) In the diagram above, show the impact of this tax or subsidy by carefully
drawing all the necessary new curves. (1 mark)
The government should introduce a lump-sum tax in order to increase AC without affecting
MC. The size of the lump-sum tax should be $140,000, so AC would increase by $10 at the
level of output (14,000) at which allocative efficiency is achieved and then P = AC = 90.
3. Negative Externalities (12 marks)
Empirical studies show a causal relationship between cigarette consumption and the incidence
of lung cancer among smokers and also among those exposed to second-hand smoke.
Therefore, cigarette consumption imposes costs also on people who do not smoke – not only is
the health of those exposed to second-hand smoke affected but also society as a whole has to
cover the additional medical cost of treating all those affected by the consumption of tobacco.
The diagram below illustrates the market supply and market demand curves for cigarettes.
MCS
Price (dollars)
15
Deadweight
loss
S = MCP
Tax = $4
10
PC = $9
7
A
PP = $5
D = MBP = MBS
100 120
180 200
300
Cigarette (thousand packs/month)
Page 5 of 11
a) What are the market equilibrium price and market equilibrium quantity of cigarette packs?
Indicate this equilibrium in the diagram above (point A). (2 marks)
P=$
7
Quantity =
180
packs/month
b) In the diagram above, draw the social marginal cost (MCS) curve assuming that the
consumption of each pack of cigarettes imposes and additional cost of $4 to society. (2
marks) What is the allocatively efficient quantity of cigarette packs? (1 mark)
Efficient quantity =
120
packs/month
c) In your diagram, shade the area corresponding to the net cost imposed on society
(“deadweight loss”) by the allocatively inefficient quantity of cigarette packs of part a). (2
marks)
d) Explain the options open to the government to achieve the allocative efficient quantity of
cigarette packs. (3 marks)
The government should impose a unit tax equal to the negative externality (i.e., $4 per pack)
in order to increase the private marginal cost to the level of the social marginal cost. In this
way the supply curve would shift up and coincide with the MCS curve.
e) If allocative efficiency is achieved by following the above option, what price will consumers
pay per pack of cigarettes? What price will producers receive per pack of cigarettes? Show
these outcomes in the diagram above. (2 marks)
PC = $
9
PP = $
5
Page 6 of 11
4. Calculation of National Accounts (12 marks)
(From Study Guide, Chapter 20) Below are data from the national accounts of a hypothetical
country. Assume that all relevant items you need to answer the questions have been provided.
Wages and salaries
Indirect taxes minus subsidies
Corporate profits before taxes
Imports
Net unincorporated business income
Investment
800
40
300
140
50
200
Depreciation
Undistributed corporate profits
Corporate profits taxes
Exports
Consumption
Interest and rental income
60
80
170
130
920
200
Use the above data to answer the following questions:
a) What is the value of net domestic income? (3 marks) [Note: Show all your work.]
NDI = wages (800) + corporate profits (300) + interest and rental income (200) + net
unincorporated business income (50) = 1350
b) What is the value of gross domestic product? (2 marks) [Note: Show all your work.]
GDP = NDI (1350) + depreciation (60) + indirect taxes minus subsidies (40) = 1450
c) What is the value of government expenditure on goods and services? (3 marks) [Note:
Show all your work.]
G = GDP (1450) – consumption (920) – investment (200) – exports (130) + imports
(140) = 340
d) What is the value of net investment? (2 marks) [Note: Show all your work.]
Net investment = gross investment (200) – depreciation (60) = 140
e) What is the value of dividends? (2 marks) [Note: Show all your work.]
Dividends = corporate profits (300) – undistributed profits (80) – corporate taxes (170) = 50
Page 7 of 11
PART II (50 marks)
Instructions:
• Multiple choice questions are to be answered using a black pencil or a black or blue ballpoint pen on the separate SCANTRON sheet being supplied.
• Be sure to fill in your name and student number on the SCANTRON sheet!
• Each question is worth 2.5 marks. No deductions will be made for incorrect answers.
• Write your answers to the multiple choice questions ALSO in the table below. You may
use this question booklet for rough work, and then transfer your answers to each multiple
choice question onto the separate SCANTRON sheet. Your answers must be on the
SCANTRON sheet. In case of a disagreement, the answer to be marked is the one on the
SCANTRON sheet.
1
2
3
4
5
6
7
8
9
10
D
C
A
E
D
B
B
C
B
D
11
12
13
14
15
16
17
18
19
20
B
A
D
C
D
C
B
E
A
B
1. (From May/2005 exam) A perfectly competitive industry is in long-run equilibrium with a
constant cost industry supply curve. The government imposes a specific commodity tax of
$2.00 per unit of output. As a result, which one of the following statements is correct in the
long run?
A) Consumer price would increase, but not by $2.00, and industry output would fall.
B) Industry output would increase and consumer price would be unchanged.
C) Industry output would decrease and consumer price would decrease.
D) Consumer price will increase by $2.00 and industry output would fall.
E) None of the above is correct.
2. (From May/2005 exam) Suppose all of the firms in a perfectly competitive industry form a
cartel and agree to restrict output, thereby raising the price of the product. Individual firm A
will gain the most from the existence of the cartel if
A) all firms, including A, cooperate and restrict output.
B) firm A restricts output, while the other firms do not.
C) all firms, except A, cooperate and restrict output.
D) no firms restrict output.
E) all firms revert back to their competitive outputs.
3. (From May/2005 exam) A perfectly competitive industry is in long-run equilibrium. Under
these conditions, which one of the following statements is correct for a typical firm?
A) Marginal revenue, marginal cost, average revenue and average cost are equal.
B) Marginal revenue equal marginal cost but not average revenue and average cost.
C) Marginal revenue equals average revenue but not marginal cost and average total
cost.
D) Marginal revenue equals average total cost but not marginal cost and average
revenue.
E) None of the above is correct.
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4. (From May/2006 exam) Suppose a competitive industry is initially in long-run equilibrium. If
this industry faces a decrease in demand for its product, the theory of perfect competition
predicts that in the long run
A) newer, more efficient firms will enter the industry and earn normal profits.
B) existing firms will modernize plant and equipment in order to increase efficiency.
C) existing firms will expand output as a means of recovering losses.
D) the industry will raise its price to earn higher revenue.
E) capacity in the industry will gradually shrink.
5. (From May/2006 exam) Comparing the short-run and long-run profit-maximizing positions of
a perfectly competitive firm, which one of the following statements is true?
A) Price will equal marginal cost in the short run, but not necessarily in the long run.
B) Economic profits may exist in the short run and in the long run.
C) In order to profit maximize, the firm must always produce at the minimum of average
total cost in the short run and in the long run.
D) The price must equal average total cost in the long run, but not necessarily in the
short run.
E) None of the above is true.
6. (From May/2006 exam) Suppose a typical competitive firm has the following data in the
short-run equilibrium: price = $10; output = 100 units; ATC = $12; AVC = $7. Which of the
following statements is correct?
A) In the long run the industry will expand because of economic profits.
B) In the long run the industry will contract because firms are suffering losses.
C) The size of the industry will remain the same in the long run.
D) Price will fall in the long run.
E) There is not enough information to formulate an answer about the long run.
7. (From May/2004 exam) A perfectly competitive industry is in short run equilibrium. Each
firm is initially making economic profits of $100,000 per year. Now, each firm faces an
increase in property taxes of $40,000 per year. As a result of this shock, which one of the
following statements is correct?
A) Each firm would shut down.
B) Each firm would produce an unchanged output and make economic profits of
$60,000.
C) Each firm would produce an increased output and make economic profits of more
than $60,000 but less than $100,000.
D) Each firm would produce a lower output and make economic profits of more than
$60,000 but less than $100,000.
E) None of the above is correct.
8. (From May/2007 exam) Suppose a firm is maximizing profits where price is $10 and
marginal revenue is $8. Given the above, which of the following we do NOT know with
certainty?
A) Price elasticity is greater than one.
B) The firm is not perfectly competitive.
C) The firm is making a profit.
D) Total revenue is increasing (as output increases).
E) Price exceeds marginal cost.
Page 9 of 11
9. (From May/2005 exam) If the monopolist operated in the inelastic range of his demand
curve,
A) he would be operating where his average revenue is negative.
B) his marginal revenue would be negative.
C) his marginal revenue would be negative although his total receipts would be at a
maximum.
D) he could raise his total revenue by lowering his price.
E) he would be operating at his profit maximizing position.
10. (From May/2006 exam) When the monopolist charges a price where the price elasticity of
demand equals 1, which of the following statement is correct?
A) Total revenue is rising, although marginal revenue is falling.
B) Total revenue is falling.
C) Total profit is at a maximum.
D) Total revenue is at a maximum.
E) None of the above is correct.
11. (From May/2008 exam) The marginal revenue curve of an unregulated, single price
monopolist lies below the demand curve because
A) the demand curve is unit elastic.
B) the monopolist must lower price on all units sold in order to sell additional units.
C) the monopolist is a price taker.
D) the marginal revenue curve coincides with the average revenue curve.
E) the marginal revenue curve is linear.
12. (From Test 2 – Summer 2008) If an unregulated profit-maximizing monopolist is producing
an output at which marginal cost exceeds marginal revenue, it
A) should raise price and reduce output.
B) should lower price and raise output.
C) is incurring losses.
D) is maximizing profits.
E) should lower price and output.
13. (From May/2008 exam) A monopolist can sell 50 units of output per day for a price of $20
each and 51 units for a price of $19 each. What is the marginal revenue of the 51st unit sold?
A) $0.
B) $1.
C) $19.
D) -$31.
E) $969.
14. (From Test 2 – Summer 2008) If a perfectly competitive industry is characterized by
constant costs in the long run, then a decrease in demand will, in the long run, lead to
A) a decrease in quantity and a decrease in price.
B) a decrease in quantity and an increase in price.
C) a decrease in quantity and no change in price.
D) no change in quantity and no change in price.
E) an increase in quantity and no change in price.
Page 10 of 11
15. (From Test 2 – Summer 2008) Externalities are likely to lead to an inefficient allocation of
resources because
A) they create benefits or costs not borne by anyone.
B) they are associated with monopolies.
C) they involved fixed costs that are not a part of marginal cost.
D) market demands and supplies do not reflect all the additional social benefits or costs.
E) people behave selfishly.
16. (From Test 2 – Summer 2008) Which of the following is NOT considered an investment
item when measuring GDP?
A) Increase in inventories of unsold goods at a warehouse owned by The Bay.
B) Purchase of new bottling equipment by a Niagara winery.
C) Purchase of 2000 shares of Sears Canada by a mutual fund company.
D) Construction of a new condo apartment tower.
E) Purchase of a new limousine for the transportation of the President of the Raptors.
17. (From Test 2 – Summer 2008) How much would the production of a kayak add to GDP in
Canada if the kayak was purchased in the United States for $250, painted in Canada for
$20, and sold by a dealer in Canada to his customer for $800?
A) $800.
B) $550.
C) $530.
D) $20.
E) $270.
18. (From May/2004 exam) In July 2003, a dealership in Toronto bought 40 brand new cars
from the Ford Motor Company at a cost of $15,000 per car. Before the end of the year this
dealership was able to sell 20 of these cars at a price of $20,000 each. The remaining cars
were sold in January 2004 at a price of $18,000 each. In these transactions, what is the
contribution of this dealership to GDP in the year 2003?
A) 760,000
B) 600,000
C) 400,000
D) 160,000
E) 100,000
19. (From August/2005 exam) Which one of the following statements about investment is
correct?
A) Net investment may be negative.
B) Net investment includes the total of all machinery and equipment produced during
the year.
C) Gross investment must equal net investment.
D) Gross investment plus depreciation equals net investment.
E) None of the above is correct.
20. (From May/2005 exam) Suppose that in 1999, ABC Corporation produced $18 million worth
of natural gas pipes but was able to sell only $16 million worth. Is the remaining $2 million
increase in inventories part of GDP for 1999?
A) Yes, since changes in inventories are part of consumption expenditures.
B) Yes, since they are part of the economy’s output in 1999.
C) No, since changes in inventories are part of actual investment.
D) No, since they are part of the economy’s output only when sold.
E) None of the above.
Page 11 of 11