Econ 201 — Final — Winter 2008 — SOLUTIONS
1
Multiple Choice - 50 Points
(In this section each question is worth 1 point)
1. Suppose a waiter deposits his cash tips into his savings account. As a result of only this
transaction:
(a) M2 increases.
(b) M1 decreases.
(c) M2 decreases.
(d) M3 increases.
2. Mark Twain said:
(a) It is easy to write 30 pages in 2 days
(b) It is easy to write 2 pages in 30 days
(c) It is easy to write 2 pages in 2 days
(d) It is easy to write 30 pages in 30 days
(e) (a) and (b)
(f) (c) and (d)
3. On 11/04/04, a euro was worth $1.287, and on 03/07/08, a euro was worth $1.535. Using
natural logarithms to calculate the total percent change between these two dates (not annualized), which is true?
(a) The dollar appreciated by 19.3%
(b) The dollar appreciated by 17.6%
(c) The dollar depreciated by 17.6%
(d) The dollar depreciated by 19.3%
4. Suppose the economy is in equilibrium and the central bank sells bonds. What happens to
the equilibrium quantity of money and interest rates in the short term?
(a) Quantity will go up, interest rates will go up.
(b) Quantity will go up, interest rates will go down.
(c) Quantity will go down, interest rates will go up.
(d) Quantity will go down, interest rates will go down.
5. The survey that produces the monthly data on the unemployment rate is based on
(a) A survey of employers
(b) A survey of employees
(c) A survey of households
(d) A survey of individuals
(e) (b) and (d)
(f) (a) and (c)
6. Suppose that Crimson Bank has excess reserves of $800 and the reserve ratio is 20%. If Niels
deposits $1,000 of cash into his checking account at Crimson Bank, and then Crimson Bank
lends $600 to Mary, what is the most that Crimson Bank can lend to Professor Gordon?
(a) $200 (b) $800 (c) $1000 (d) $2400
Pg. 2
7. Consider the market for loanable funds. Other things being equal, an increase in taxes on
savings and investment income will:
(a) shift demand to the right and increase the interest rate.
(b) shift demand to the left and decrease the interest rate.
(c) shift supply to the right and decrease the interest rate.
(d) shift supply to the left and increase the interest rate.
8. American jobs are lost to:
(a) China in manufacturing
(b) China in information technology services
(c) India in manufacturing
(d) India in information technology services
(e) (b) and (c)
(f ) (a) and (d)
9. Which of the following will not cause the AD curve to shift to the left?
(a) Higher income tax rate
(b) Lower stock of physical capital
(c) Open-market purchase
(d) Lower government spending
(e) (b) and (c)
10. An example of a double coincidence of wants is:
(a) a car mechanic who wants a TV finding an owner of an electronics store
who wants a car repaired.
(b) a car dealer who wants a TV finding an electronics store owner who wants money.
(c) an electronics store owner who wants car repairs finding a car mechanic who wants money.
(d) all of the above are examples.
11. What is the main reason that the government does not bail out the households who face
foreclosure on their mortgages?
(a) Fear of higher inflation
(b) Fear of lower output
(c) Moral hazard
(d) Bankruptcy of the mortgage banking industry
12. Advocates of free trade claim that
(a) Import competitors are winners and consumers are losers
(b) Consumers are losers and import competitors are losers
(c) Consumers are losers and export producers are winners
(d) Consumers are winners and export producers are winners
13. If a bank has deposits of $100,000, loans of $200,000, cash on hand of $10,000, and $15,000
on deposit at the Federal Reserve, then its reserve ratio is:
(a) 5% (b) 10% (c) 12.5% (d) 25%
14. If the nominal quantity of money is $4 trillion, real output is $10 trillion, and the price level
is 2, then the velocity of money is:
(a) 1 (b) 2 (c) 4 (d) 5
Pg. 3
15. To
the money supply, the Fed could
(a) decrease; lower the discount rate
(b) increase; raise the federal funds rate
(c) decrease; conduct open-market purchases
(d) increase; lower the required reserve ratio
.
16. Japan’s “lost decade” and today’s U.S. mortgage meltdown have one thing in common, which
is:
(a) Falling housing prices.
(b) Aggressive use of stimulative monetary and fiscal policy.
(c) Insolvent banks.
(d) Use of cash for most transactions.
17. An increase in the price level
(a) increases the nominal demand for money.
(b) decreases the nominal demand for money.
(c) does not affect the nominal demand for money.
(d) shifts the nominal demand for money to the left.
18. The money demand curve is
because a lower interest rate
(a) upward-sloping; increases the opportunity cost of holding money.
(b) downward-sloping; increases the opportunity cost of holding money.
(c) upward-sloping; decreases the opportunity cost of holding money.
(d) downward-sloping; decreases the opportunity cost of holding money
.
19. If the economy is suffering from a recessionary gap, the Fed should conduct
monetary policy by
the money supply.
(a) expansionary; decreasing
(b) expansionary; increasing
(c) contractionary; decreasing
(d) contractionary; increasing
20. In the readings for Chapter 19, there is a debate in Business Week about the desirability of
letting the dollar depreciate. Which of the following is not an argument in favor of letting
the dollar depreciate?
(a) It will make U.S. exports more competitive.
(b) It will make U.S. imports more expensive.
(c) It will defuse protectionist pressure.
(d) It will attract more investment for the U.S. stock market.
21. Deflation depresses aggregate demand because of
(a) The wealth effect
(b) The expectations effect
(c) The income effect
(d) The consumption effect
Pg. 4
22. Suppose the AD, LRAS, and SRAS curves in the economy are
Aggregate
Price
Level
LRAS
SRAS
Y
AD
Real GDP
If real GDP in the economy is at Y and the central bank wants to change real GDP in the
short-run to be equal to potential GDP it should:
(a) Buy bonds on the open market.
(b) Sell bonds on the open market.
(c) Do nothing.
(d) Tell the government to print more money.
23. Economists argue that money is neutral:
(a) in both the short and long run.
(b) in the short run only.
(c) in the long run but does have an impact on the price level.
(d) in the long run but has no impact on the price level.
24. When an economy moves from autarky to free international trade, in the export sector
(a) consumer and producer surplus both rise and the economy as a whole gains.
(b) consumer surplus rises, producer surplus falls, and the economy as a whole gains.
(c) consumer surplus falls, producer surplus rises, and the economy as a whole
gains.
(d) the decrease in either consumer surplus or producer surplus is sufficiently large to cause
net losses for the economy.
25. Initially, the nominal exchange rate is 0.7 euros per $, and the price index for both the U.S.
and the euro area are each 100. Over the following 10 years, the annual U.S. inflation rate is
3.5% per year, and that of the euro area is 2.5% per year. What must the nominal exchange
rate be after 10 years to maintain the initial real exchange rate?
(a) 0.5 euros per $
(b) 0.62 euros per $
(c) 0.7 euros per $
(d) 0.77 euros per $
26. The three main monetary policy tools are:
(a) interest rates, taxes, government purchases, and transfers.
(b) currency, near-moneys, and reserve ratio.
(c) deposit insurance, discount rate, and money multiplier.
(d) reserve requirements, the discount rate, and open-market purchases.
Pg. 5
For the next three problems, consider the following chart showing supply and demand for
calculators.
Price of
calculators
Domestic supply
$300
A
$150
B
$120
PW = $100
C
K
G
L
H
I
J
F
Domestic demand
$50
35
50
60
Quantity of
calculators
27. The world price, PW , equals $100. When the economy moves from autarky to free trade,
consumer surplus rises by area
and producer surplus falls by
.
(a) B + K + L; B
(b) B + C + K + L; B + C + K + L
(c) B + C+ H + I + K + L; B + C + H + I
(d) B + C + G + H + I + J + K + L;
B+C
28. The world price, PW , equals $100. The government imposes a quota restricting imports to
25 calculators. If the import licenses are granted to foreigners, the net loss due to the import
quota is equal to areas:
(a) K + L
(b) G + J
(c) G + H + I + J
(d) G + H + I + J + K + L
29. The world price, PW , equals $100. The government imposes an import tariff of $20 per calculator.
Compared with the free trade situation, the tariff leads to a deadweight loss equal to areas:
(a) K + L
(b) G + J
(c) G + H + I + J
(d) There is no deadweight loss, since the tariff revenue the government receives offsets any losses.
30. The CPI in September, 2007, was 208.3, and it was 211.2 in December, 2007. The annualized
growth rate between September and December was:
(a) 1.38% (b) 2.44% (c) 3.84% (d) 5.53%
Pg. 6
31. In the absence of international capital flows, the equilibrium interest rate in the U.S. market
for loanable funds is 3%, while in Germany it is 7%. International borrowing and lending between the United States and Germany may result in a common interest rate of
and
.
(a) 4%; capital inflows to the United States matching the capital outflows from Germany
(b) 3%; massive capital inflows from Germany into the United States
(c) 5%; capital outflows from the United States matching the capital inflows into
Germany
(d) 7%; massive capital inflows from the United States into Germany
32. All else being equal, which of the following could cause exchange rates to change from
1e=$1.50 to 1e=$1.25?
(a) interest rates are higher in Europe.
(b) interest rates are higher in the United States.
(c) interest rates in the United States and Europe are equal.
(d) inflation is higher in Europe.
33. A Nobel-Prize winner suggested the following combination:
(a) Developed countries should lower tariffs and less-developed countries should
raise tariffs
(b) Developed countries should raise tariffs and less-developed countries should reduce tariffs
(c) Developed countries should lower tariffs and less-developed countries should reduce tariffs
(d) Developed countries should raise tariffs and less-developed countries should raise tariffs
34. Which of the following is true of the 2006 international balance of payments of the U.S.?
(a) Current account surplus; private financial inflows > official financial inflows
(b) Current account surplus; official financial inflows > private financial inflows
(c) Current account deficit; private financial inflows > official financial inflows
(d) Current account deficit; official financial inflows > private financial inflows
35. Suppose exchange rates between the U.S. and Europe changed from 1e=$1.50 to 1e=$1.25.
This would cause Americans to purchase
goods and services from Europe.
(a) the same amount of
(b) fewer
(c) more
(d) none of the above
36. Expansionary monetary policy in the United States causes U.S. interest rates to
and the dollar to
.
(a) increase; appreciate (b) increase; depreciate
(c) decrease; appreciate (d) decrease; depreciate
37. The U.S. rates lower on indices of well-being than on real per capita GDP because
(a) The U.S. ranks lower on life expectancy
(b) The U.S. ranks lower on health care expenditures as a share of GDP
(c) The U.S. ranks lower in science and math test scores
(d) The U.S. ranks lower on energy spending as a share of GDP
Pg. 7
38. A reason for the low U.S. household saving rate is
(a) Americans do not care about saving for their children
(b) Americans respond to rising imports by spending now
(c) Americans respond to capital gains on housing
(d) High American investment crowds out saving
39. Suppose the reserve requirement is 20%, and you deposit a $1,000 check received as a gift for
acing this exam in your checking account. The bank does NOT want to hold excess reserves.
By how much does the monetary base change?
(a) $0 (b) $800 (c) $1000 (d) $4000 (e) $5000
40. The order of magnitude increase in prices between 1929 and 2007 was by a factor of
(a) 2 (b) 5 (c) 10 (d) 20 (e) 40
41. A myth about the Great Depression is that
(a) The New Deal ended the Great Depression
(b) The New Deal raised the price level
(c) The New Deal raised the wage level
(d) The New Deal raised interest rates
42. Consider the following table which shows the maximum amounts of machinery and petroleum
that the United States and Mexico can produce if they only produce one good. Both nations
face constant costs of production.
Countries
United States
Mexico
Machinery (units)
80
60
The United States has a comparative advantage in
.
parative advantage in
(a) both goods; neither good
(b) neither good; both goods
(c) machinery; petroleum
(d) petroleum; machinery
Petroleum (units)
40
180
, and Mexico has a com-
43. The table shows the maximum amounts of autos and clothing that the United States and
Canada can produce if they only produce one good. Both nations face constant costs of
production.
Countries
United States
Canada
Autos (units)
80
60
Clothing (units)
40
30
Given the opportunity costs of production:
(a) there is no basis for trade.
(b) Canada should specialize in clothing.
(c) the United States should specialize in autos.
(d) the United States should specialize in both goods, and Canada should not produce either good.
Pg. 8
44. Suppose actual output is below potential output. In the long run:
(a) nominal wages will decrease, and the short-run supply curve will shift to the
right.
(b) nominal wages will increase, and the short-run supply curve will shift to the left.
(c) the aggregate demand curve will shift to the right.
(d) the long-run aggregate supply curve will shift to the right.
45. Suppose M P C = 0.6 and t = 0.25. Holding all else constant, if capital inflows goes up by
100, how much does equilibrium Y change?
(a) Y goes up by about 182
(b) Y goes down by about 182
(c) Y goes up by about 333
(d) Y goes down by about 333
46. The circle to the left of George Washington’s picture on the $1 bill represents:
(a) The Presidential Seal
(b) The importance of the number ”13” in the design of the bill
(c) The regional Federal reserve bank that issued the bill
(d) The roman numeral for 1776 at the base of the pyramid
47. In the twentieth century, the years with the largest inflationary gap were:
(a) 1932-35 (b) 1942-45 (c) 1952-55 (d) 1962-65
48. Suppose that annual inflation is 2% and the annual growth rate of real GDP is 3%. What is
the annual growth rate of nominal GDP?
(a) 1%
(b) 2%
(c) 3%
(d) 4%
(e) 5%
(f) 6%
49. The course packet delivers a condemnation of Alan Greenspan’s reign at the Federal Reserve
between 1987 and 2006. Which of these comes closest to the condemnation?
(a) Keeping interest rates too low in 1987-91
(b) Keeping interest rates too low in 1992-96
(c) Keeping interest rates too low in 1997-2001
(d) Keeping interest rates too low in 2001-2005
50. An aggregate production function typically exhibits
respect to capital per worker.
(a) Increasing
(b) Decreasing
(c) Constant
(d) Zero
returns to scale with
Pg. 9
2
Short Answer - 70 points
PLEASE NOTE: In order to receive full credit, in calculating growth rates you must
use the logarithmic or exponential formulas from the classroom handout.
1. (14 pts.) Consider the economy of the country Microvilleshire. Its short-run aggregate supply
and aggregate demand equations are described as follows:
SRAS: CPI = 20 + 6Y
AD: CPI = 60 − 4Y
(a) Suppose Microvilleshire is in long-run equilibrium.
• (2 pts.) What is output in the long-run?
SOLUTION: We are told Microvilleshire is in long-run equilibrium, so we can just
find the short-run equilibrium, and we know that’s the same as the long-run one.
20 + 6Y = 60 − 4Y ⇒ Y = 4
• (2 pts.) What is CPI in the long-run?
SOLUTION: CPI = 20 + 6 · 4 = 44
• (3 pts.) Draw a graph of aggregate supply and aggregate demand that illustrates
AD, SRAS, and LRAS.
SOLUTION: The graph should have CPI on the y-axis and Y on the x-axis, and it
should include SRAS, which has intercept 20 and slope 6, AD, which has intercept
60 and slope -4, as well as LRAS, which is vertical. All three lines should cross at
Y = 4 and CPI = 44.
(b) Now suppose that Microvilleshire’s main trade partner, Macrovilleshire, changes their
trade policy in a way that decreases their demand for Microvilleshire products. This
shifts AD such that for every level of output, the CPI is decreased by 30.
• (1 pt.) Does this result in a inflationary gap, a recessionary gap, or no output gap
of any sort?
SOLUTION: AD falls ⇒ Y falls ⇒ recessionary gap.
• (2 pts.) If you think there is an inflationary or recessionary gap, what is the magnitude? If you think there is no output gap, explain why.
SOLUTION: The new AD curve is CPI = 30 − 4Y . Setting SRAS=AD, we get
30 − 4Y = 20 + 6Y ⇒ Y = 1. So, the recessionary gap is 4 − 1 = 3.
• (1 pt.) Change your graph above in (a) to include the new AD and the inflationary
or recessionary gap you found.
SOLUTION: There should be a forth line added to the graph: the new AD curve,
which has intercept 30 and slope -4. It should cross the old SRAS line at Y = 1 and
CPI = 26.
(c) (3 pts.) What is the new long-run equilibrium output and long-run equilibrium CPI?
SOLUTION: Long-run output is still Y = 4. The new long-run prices will be CPI
= 30 − 4 · 4 = 14.
Pg. 10
2. (14 pts.) Consider a closed economy with three types of goods: consumption goods, investment goods, and government-purchased goods. In 2000, data on these goods is given
by:
2000
Consumption goods:
Investment goods:
Government goods:
Average Price
$100
$700
$500
Quantity
1400
900
700
After 2000, the Federal Reserve decreases the money supply, and the government engages in
expansionary fiscal policy. This leads to the following data for 2001:
2001
Consumption goods:
Investment goods:
Government goods:
Average Price
$90
$650
$600
Quantity
1300
750
850
(a) (2 pts.) What is nominal GDP in 2000 and 2001?
SOLUTION: GDP in 2000 = 100 · 1400 + 700 · 900 + 500 · 700 = 1120000 GDP in 2001
= 90 · 1300 + 650 · 750 + 600 · 850 = 1114500
(b)
• (1 pt.) Using base year 2000, what is real GDP in 2001?
SOLUTION: Real GDP in 2001 using 2000 as base year = 100 · 1300 + 700 · 750 +
500 · 850 = 1080000
• (1 pt.) Using base year 2001, what is real GDP in 2000?
SOLUTION: Real GDP in 2000 using 2001 as base year = 90 · 1400 + 650 · 900 +
600 · 700 = 1131000
(c) (6 pts.) Using the GDP deflator as your price index, what is the chain-weighted inflation
rate between 2000 and 2001?
1120000
SOLUTION: Using 2000 as base year, GDP deflator in 2000 = 1120000
· 100 = 100
1114500
Using 2000 as base year, GDP deflator
in
2001
=
·
100
=
103.194
Using
2000 as
1080000
103.194
= 3.1445%. Using 2001 as base year, GDP deflator
base year, inflation = ln 100
in 2000 = 1120000
·
100
=
99.0274.
Using 2001 as base year, GDP deflator in 2001
1131000
100
1114500
= 1114500
· 100 = 100. Using 2001 as base year, inflation = ln 99.0274
= 0.9774%. So,
0.031445+0.009774
chain-weighted inflation =
= 2.0609%.
2
(d)
• (1 pt.) Write the equation that relates the velocity of money (call it V ) to the money
supply and nominal GDP.
SOLUTION: M · V = P · Y ⇒ V = PM·Y = nominal GDP
money supply
• (3 pts.) Suppose that in 2000, the money supply was $224,000. Assume that the
velocity of money is the same in 2000 and 2001. Use the values of nominal GDP
you found in part (a) for 2000 and 2001 to calculate the money supply in 2001.
SOLUTION: V = nominal GDP = 1120000
224000 = 5. Since V is the same in 2001, we
money supply
1114500
= 222900.
have M · 5 = nominal GDP ⇒ M =
5
Pg. 11
3. (17 pts.) Consider an economy in equilibrium with the following initial structure:
Equilibrium GDP = Y = 10, 000
M P C = 34
Income tax rate = t = 91
Reserve ratio = rr = 0.10
The desired currency to deposit ratio is 15%, so c = 0.15
Interest rate = i = 0.04 (= 4%)
Money demand is characterized by M D = 550 − 1000i (in millions of dollars, where i is
written as a decimal. For example, if i = 0.07, then M D = 550 − 1000 · 0.07 = 480).
Assume consumption takes the standard form C = A + M P C · (Y − T ), and taxes take the
form T = Ta + t · Y .
A, Ta , t, G, X, Im, and M P C do not change when the interest rate changes. However,
investment does change based on the interest rate. Specifically, I = 1000 − 5000i.
(Again, i is written as a decimal. For example, if i = 0.07, then I = 1000 − 5000 · 0.07 = 650.)
(a) Given that the economy is in equilibrium:
• (2 pts.) What is the money supply? (Hint: consider the market for money and the
equilibrium condition that relates M D to M S )
SOLUTION: M S = M D = 550 − 1000 · 0.04 = 510
• (2 pts.) What is the monetary base?
S
550
SOLUTION: B = M
1+c = 1.15 = 110.87
c+rr
0.25
(b) (2 pts.) Now suppose that the central bank sells 5 million dollars worth of bonds on the
open market. What is the change in money supply?
1+c
SOLUTION: ∆M S = c+rr
∆B = 1.15
0.25 · (−5) = −23
(c) (2 pts.) What is the new interest rate?
SOLUTION: M S = M D ⇒ 510 − 487 = 550 − 1000 · i ⇒ i = 0.063
(d) (4 pts.) What is the new equilibrium Y that results from the open market operation
described in parts (b) and (c)? (Hint: first, find how I changes.)
SOLUTION: ∆I = (1000 − 5000 · 0.04) − (1000 − 5000 · 0.063) = −115
−115
∆Y = 1−M P∆I
C·(1−t) = 1−0.75 8 = −345 ⇒ Y = 9655
9
(e) (5 pts.) Going back to the initial equilibrium (i.e., before the open market operations in
(b) happened), suppose that net exports decreases by 100 and G increases by 20. The
central bank wants to keep output unchanged (i.e., wants to keep Y = 10, 000). How
many million dollars of bonds should they buy or sell?
SOLUTION: We want the change in I to offset the change in N X and G. If the Fed
does nothing, we will have ∆AAE = 20 − 100 = −80. So, we want ∆I = 80 to offset the
changes. This means we want a new level of investment of I = (1000 − 5000 · 0.04) + 80 =
880. If I = 880, we need an interest rate of 880 = 1000 − 5000 · i ⇒ i = 0.024. In
order to have i = 0.024, we need M S = 550 − 1000 · 0.024 = 526. Thus, we need a
change in M S of ∆M S = 526 − 510 = 16. This means we needs a change in B of
S
16
∆B = ∆M
1+c = 1.15 = 3.47826. Thus, the Fed needs to buy 3.47826 million dollars worth
c+rr
of bonds.
0.25
Pg. 12
4. (25 pts.) Suppose an economy has the following data:
Year
2004
2005
2006
Y
YD
C
700
800
I
200
220
250
G
150
200
200
X
200
300
300
Im
150
170
T
100
150
NS
The consumption function and the tax function are the same in every year.
Additionally, imports are a function of disposable income. In particular, the import function
is Im = a + b · YD where a and b are some numbers. This function also stays the same
every year.
(a) (2 pts.) What is Y (GDP or output) and YD (disposable income) in 2004 and 2005?
SOLUTION: Y = C + I + G + X − Im. In 2004, Y = 700 + 200 + 150 + 200 − 150 =
1100. In 2005, Y = 800 + 220 + 200 + 300 − 170 = 1350. YD = Y − T . In 2004,
YD = 1100 − 100 = 1000. In 2005, YD = 1350 − 150 = 1200.
(b) (2 pts.) What are national savings in 2004 and 2005?
SOLUTION: N S = P S + GS = Y − T − C + T − G = Y − C − G. In 2004,
N S = 1100 − 700 − 150 = 250. In 2005, N S = 1350 − 800 − 200 = 350.
(c) (Hint: for the three sections in part (c), use the data for 2004 and 2005.)
• (3 pts.) What is the consumption function? (Hint: your answer should be of the
form C = A + M P C · YD .)
SOLUTION: The two equations to solve are: 700 = A + M P C · 1000 and 800 =
A + M P C · 1200. These give M P C = 0.5 and A = 200. Thus, the consumption
function is C = 200 + 0.5 · YD .
• (3 pts.) What is the tax function? (Hint: your answer should be of the form
T = Ta + t · Y .)
SOLUTION: The two equations to solve are: 100 = Ta + t · 1100 and 150 =
Ta + t · 1350. These give t = 0.20 and Ta = −120. Thus, the tax function is
T = −120 + 0.20 · Y .
• (3 pts.) What is the import function? (Hint: as above, your answer should be of
the form Im = a + b · YD .)
SOLUTION: The two equations to solve are: 150 = a+b·1000 and 170 = a+b·1200.
These give b = 0.10 and a = 50. Thus, the import function is Im = 50 + 0.10 · YD .
(d) (Hint: you should be using the three functions you found in part (c), along with the
data from the table for 2006, to help solve for Y .)
SOLUTION: Y = C + I + G + X − Im ⇒ Y = A + M P C · (Y − (Ta + t · Y )) + I +
P C·Ta +I+G+X−a+b·Ta
G + X − (a + b · (Y − (Ta + t · Y ))) ⇒ Y = A−M
1−M P C·(1−t)+b·(1−t)
• (2 pts.) What is the multiplier for 2006?
1
1
SOLUTION: From above, the multiplier is 1−M P C·(1−t)+b·(1−t)
= 1−0.5(1−0.2)+0.10(1−0.2)
=
1.4706
• (2 pts.) What is AAE for 2006?
SOLUTION: From above, AAE= A − M P C · Ta + I + G + X − a + b · Ta =
200 − 0.5(−120) + 250 + 200 + 300 − 50 + 0.10(−120) = 948
Pg. 13
• (1 pt.) What is equilibrium GDP for 2006?
SOLUTION: Y = 948 · 1.4706 = 1394.12
(e) (2 pts.) What is the trade balance in equilibrium in 2006?
SOLUTION: Trade balance= X−Im = 300−(50+0.10·(1394.12 − (−120 + 0.2 · 1394.12))) =
126.47
(f) (3 pts.) Now suppose that the government changes the tax policy by decreasing Ta by
80. By how much does equilibrium GDP change? (Hint: use the formula you found for
Y in part (d).)
−0.5(−80)+0.1(−80)
−M P C·∆Ta +b·∆Ta
∆AAE
SOLUTION: ∆Y = 1−M P C·(1−t)+b(1−t)
= 1−M
P C·(1−t)+b(1−t) = 1−0.5(1−0.2)+0.10(1−0.2) =
47.0588
(g) Return to part (d) (i.e., ignore the change in part (f)). Suppose between 2006 and 2007,
M P C changes to 0.70, and t changes to 0 (no income tax).
• (1 pt.) What is the new multiplier in 2007?
1
SOLUTION: Multiplier = 1−M P C·(1−t)+b(1−t)
=
1
1−0.7(1−0)+0.10(1−0)
= 2.5
• (1 pt.) Assume AAE is the same in 2007 as it was in 2006 (from part (d)). What is
equilibrium GDP in 2007?
SOLUTION: Y = 948 · 2.5 = 2370
NOTE: AAE does change. It’s new value is AAE = A−M P C ·Ta +I +G+X −a+b·
Ta = 200−0.7(−120)+250+200+300−50+0.1(−120) = 972 ⇒ Y = 972·2.5 = 2430