曼昆经济学原理课件(下)-宏观部分,北大作业作业3A_03_0.doc

经济学原理II（2007年春季学期）作业3第一部分：教材习题教材，第29章，问题与应用，5, 6，9，10，115.a.Here is BSBs T-account:Beleaguered State BankAssetsLiabilitiesReserves$25 millionDeposits$250 millionLoans$225 millionb.When BSBs largest depositor withdraws $10 million in cash and BSB reduces its loans outstanding to maintain the same reserve ratio, its T-account is now:Beleaguered State BankAssetsLiabilitiesReserves$24 millionDeposits$240 millionLoans$216 millionc.Since BSB is cutting back on its loans, other banks will find themselves short of reserves and they may also cut back on their loans as well.d.BSB may find it difficult to cut back on its loans immediately, since it cant force people to pay off loans. Instead, it can stop making new loans. But for a time it might find itself with more loans than it wants. It could try to attract additional deposits to get additional reserves, or borrow from another bank or from the Fed.6.If you take $100 that you held as currency and put it into the banking system, then the total amount of deposits in the banking system increases by $1,000, since a reserve ratio of 10 percent means the money multiplier is 1/.10 = 10. Thus the money supply increases by $900, since deposits increase by $1,000 but currency declines by $100.9.a.With a required reserve ratio of 10 percent and no excess reserves, the money multiplier is 1/.10 = 10. If the Fed sells $1 million of bonds, reserves will decline by $1 million and the money supply will contract by 10 x $1 million = $10 million.b.Banks might wish to hold excess reserves if they need to hold the reserves for their day-to-day operations, such as paying other banks for customers transactions, making change, cashing paychecks, and so on. If banks increase excess reserves such that theres no overall change in the total reserve ratio, then the money multiplier doesnt change and theres no effect on the money stock.10.a.With banks holding only required reserves of 10 percent, the money multiplier is 1/.10 = 10. Since reserves are $100 billion, the money stock is 10 x $100 billion = $1,000 billion.b.If the required reserve ratio is raised to 20 percent, the money multiplier declines to 1/.20 = 5. With reserves of $100 billion, the money stock would decline to $500 billion, a decline of $500 billion. Reserves would be unchanged, since all available currency would be held by banks as reserves.11.a.If people hold all money as currency, the quantity of money is $2,000.b.If people hold all money as demand deposits at banks with 100 percent reserves, the quantity of money is $2,000.c.If people have $1,000 in currency and $1,000 in demand deposits, the quantity of money is $2,000.d.If banks have a reserve ratio of 10 percent, the money multiplier is 1/.10 = 10. So if people hold all money as demand deposits, the quantity of money is 10 x $2,000 = $20,000.e.If people hold equal amounts of currency (C) and demand deposits (D) and the money multiplier for reserves is 10, then two equations must be satisfied: (1) C = D, so that people have equal amounts of currency and demand deposits; and (2) 10 x ($2,000 - C) = D, so that the money multiplier (10) times the number of dollar bills that arent being held by people ($2,000 - C) equals the amount of demand deposits (D). Using the first equation in the second gives 10 x ($2,000 - D) = D, or $20,000 - 10 D = D, or $20,000 = 11 D, so D = $1,818.18. Then C = $1,818.18. The quantity of money is C + D = $3,636.36.第30章，问题与应用，1，2，3，7，8，10，121.In this problem, all amounts are shown in billions.a.Nominal GDP = P x Y = $10,000 and Y = real GDP = $5,000, so P = (P x Y)/Y = $10,000/$5,000 = 2.Since M x V = P x Y, then V = (P x Y)/M = $10,000/$500 = 20.b.If M and V are unchanged and Y rises by 5 percent, then since M x V = P x Y, P must fall by 5 percent. As a result, nominal GDP is unchanged.c.To keep the price level stable, the Fed must increase the money supply 5 percent, matching the increase in real GDP. Then, since velocity is unchanged, the price level will be stable.d.If the Fed wants inflation to be 10 percent, it will need to increase the money supply 15 percent. Thus M x V will rise 15 percent, causing P x Y to rise 15 percent, with a 10 percent increase in prices and a 5 percent rise in real GDP.2.a.If people need to hold less cash, the demand for money shifts to the left, since there will be less money demanded at any price level.b.If the Fed doesnt respond to this event, the shift to the left of the demand for money combined with no change in the supply of money leads to a decline in the value of money (1/P), which means the price level rises, as shown in Figure 28-1.Figure 28-1c.If the Fed wants to keep the price level stable, it should reduce the money supply from S1 to S2 in Figure 28-2. This would cause the supply of money to shift to the left by the same amount that the demand for money shifted, resulting in no change in the value of money and the price level.Figure 28-23.With constant velocity, reducing the inflation rate to zero would require the money growth rate to equal the growth rate of output, not zero, according to the quantity theory of money (M x V = P x Y).6.a.When the price of both goods doubles in a year, inflation is 100 percent. The total cost of purchasing equal amounts of beans and rice equals the quantity of each good times its price, added together for all goods. That is, if x is the quantity of beans, which also equals the quantity of rice, then the cost of beans and rice for the year is x(PB + PR). In the second year, the cost is x(PB + PR), where the mark refers to the price in the second year. Then we can define a price index with a value of one in the first year. In the second year, the price index has the value of the cost of goods in the second year divided by the cost of goods in the first year. Thus the price index in the second year is x(PB + PR)/x(PB + PR) = (PB + PR)/(PB + PR) = ($2 + $6)/($1 + $3) = $8/$4 = 2. The inflation rate is then (2-1)/1 x 100% = 100%. Since the prices of all goods rise by 100 percent, the farmers get a 100 percent increase in their incomes to go along with the 100 percent increase in prices, so neither is affected by the change in prices.b.If the price of beans rises to $2 and the price of rice rises to $4, then the price index in the second year is (PB + PR)/(PB + PR) = ($2 + $4)/($1 + $3) = $6/$4 = 1.5, so the inflation rate is (1.5-1)/1 x 100% = 50%. Bob is better off because his dollar revenues doubled (increased 100%) while inflation was only 50%. Rita is worse off because inflation was 50%, so the prices of the goods she buys rose faster than the price of the goods (rice) she sells, which rose only 33%.c.If the price of beans rises to $2 and the price of rice falls to $1.50, then the price index in the second year is (PB + PR)/(PB + PR) = ($2 + $1.50)/($1 + $3) = $3.50/$4 = 0.875, so the inflation rate is (0.875-1)/1 x 100% = -12.5%. Bob is better off because his dollar revenues doubled (increased 100%) while prices overall fell 12.5%. Rita is worse off because inflation was -12.5%, so the prices of the goods she buys didnt fall as fast as the price of the goods (rice) she sells, which fell 50%.d.The relative price of rice and beans matters more to Bob and Rita than the overall inflation rate. If the price of the good that a person produces rises more than inflation, he or she will be better off. If the price of the good a person produces rises less than inflation, he or she will be worse off.7.The following table shows the relevant calculations:(a)(b)(c)(1) Nominal interest rate10.06.04.0(2) Inflation rate5.02.01.0(3) Before-tax real interest rate5.04.03.0(4) Reduced interest rate due to 40% tax4.02.41.6(5) After-tax nominal interest rate6.03.62.4(6) After-tax real interest rate1.01.61.4Row (3) is row (1) minus row (2). Row (4) is .40 x row (1). Row (5) is (1 - .40) x row (1), which equals row (1) minus row (4). Row (6) is row (5) minus row (2). Note that even though part (a) has the highest before-tax real interest rate, it has the lowest after-tax real interest rate. Note also that the after-tax real interest rate is much less than the before-tax real interest rate.10.a.Unexpectedly high inflation helps the government by providing higher inflation tax revenue and reducing the real value of outstanding government debt.b.Unexpectedly high inflation helps a homeowner with a fixed-rate mortgage because she pays a fixed nominal interest rate that was based on expected inflation, and thus pays a lower real interest rate than was expected.c.Unexpectedly high inflation hurts a union worker in the second year of a labor contract because the contract probably based the workers nominal wage on the expected inflation rate. As a result, the worker receives a lower-than-expected real wage.d.Unexpectedly high inflation hurts a college that has invested some of its endowment in government bonds because the higher inflation rate means the college is receiving a lower real interest rate than it had planned.12.a.The statement that Inflation hurts borrowers and helps lenders, because borrowers must pay a higher rate of interest, is false. Higher expected inflation means borrowers pay a higher nominal rate of interest, but its the same real rate of interest, so borrowers arent worse off and lenders arent better off. Higher unexpected inflation, on the other hand, makes borrowers better off and lenders worse off.b.The statement that If prices change in a way that leaves the overall price level unchanged, then no one is made better or worse off, is false. Changes in relative prices can make some people better off and others worse off, even though the overall price level doesnt change. See problem