经济学原理第三版习题答案.docx

1、经济学原理第三版习题答案SOLUTIONS TO TEXT PROBLEMS:Quick Quizzes1. Figure 1 shows the demand curve for turkey. The price of turkey is P1 and the consumer surplus that results from that price is denoted CS. Consumer surplus measures buyers willingness to pay (measured by the demand curve) minus the amount the bu

2、yers actually pay.Figure 1Figure 22. Figure 2 shows the supply curve for turkey. The price of turkey is P1 and the producer surplus that results from that price is denoted PS. Producer surplus measures the amount sellers are paid for a good minus the sellers cost (measured by the supply curve).Figur

3、e 33. Figure 3 shows the supply and demand for turkey. The price of turkey is P1, consumer surplus is CS, and producer surplus is PS. Producing more turkey would lower total surplus because the value to buyers would be less than the cost to sellers.Questions for Review1. Buyers willingness to pay, c

4、onsumer surplus, and the demand curve are all closely related. The height of the demand curve represents the willingness to pay of the buyers. Consumer surplus is the area below the demand curve and above the price, which equals each buyers willingness to pay less the price of the good.2. Sellers co

5、sts, producer surplus, and the supply curve are all closely related. The height of the supply curve represents the costs of the sellers. Producer surplus is the area below the price and above the supply curve, which equals the price minus each sellers costs.Figure 43. Figure 4 shows producer and con

6、sumer surplus in a supply-and-demand diagram.4. An allocation of resources is efficient if it maximizes total surplus, the sum of consumer surplus and producer surplus. But efficiency may not be the only goal of economic policymakers; they may also be concerned about equitythe fairness of the distri

7、bution of well-being.5. The invisible hand of the marketplace guides the self-interest of buyers and sellers into promoting general economic well-being. Despite decentralized decisionmaking and self-interested decisionmakers, free markets lead to an efficient outcome.6. Two types of market failure a

8、re market power and externalities. Market power may cause market outcomes to be inefficient because when firms influence prices they cause price and quantity to differ from the levels they would be under perfect competition, which keeps total surplus from being maximized. Externalities are side effe

9、cts that are not taken into account by buyers and sellers. As a result, the free market does not maximize total surplus.Problems and Applications1. If an early freeze in California sours the lemon crop, the supply curve for lemons shifts to the left, as shown in Figure 5. The result is a rise in the

10、 price of lemons and a decline in consumer surplus from A + B + C to just A. So consumer surplus declines by the amount B + C.Figure 5In the market for lemonade, the higher cost of lemons reduces the supply of lemonade, as shown in Figure 6. The result is a rise in the price of lemonade and a declin

11、e in consumer surplus from D + E + F to just D, a loss of E + F. Note that an event that affects consumer surplus in one market often has effects on consumer surplus in other markets.Figure 62. A rise in the demand for French bread leads to an increase in producer surplus in the market for French br

12、ead, as shown in Figure 7. The shift of the demand curve leads to an increased price, which increases producer surplus from area A to area A + B + C.Figure 7The increased quantity of French bread being sold increases the demand for flour, as shown in Figure 8. As a result, the price of flour rises,

13、increasing producer surplus from area D to D + E + F. Note that an event that affects producer surplus in one market leads to effects on producer surplus in related markets. Figure 83. a. Berts demand schedule is: PriceQuantity DemandedMore than $70$5 to $71$3 to $52$1 to $33$1 or less4Berts demand

14、curve is shown in Figure 9.Figure 9b. When the price of a bottle of water is $4, Bert buys two bottles of water. His consumer surplus is shown as area A in the figure. He values his first bottle of water at $7, but pays only $4 for it, so has consumer surplus of $3. He values his second bottle of wa

15、ter at $5, but pays only $4 for it, so has consumer surplus of $1. Thus Berts total consumer surplus is $3 + $1 = $4, which is the area of A in the figure.c. When the price of a bottle of water falls from $4 to $2, Bert buys three bottles of water, an increase of one. His consumer surplus consists o

16、f both areas A and B in the figure, an increase in the amount of area B. He gets consumer surplus of $5 from the first bottle ($7 value minus $2 price), $3 from the second bottle ($5 value minus $2 price), and $1 from the third bottle ($3 value minus $2 price), for a total consumer surplus of $9. Th

17、us consumer surplus rises by $5 (which is the size of area B) when the price of a bottle of water falls from $4 to $2.4. a. Ernies supply schedule for water is:PriceQuantity SuppliedMore than $74$5 to $73$3 to $52$1 to $31Less than $10Ernies supply curve is shown in Figure 10.Figure 10b. When the pr

18、ice of a bottle of water is $4, Ernie sells two bottles of water. His producer surplus is shown as area A in the figure. He receives $4 for his first bottle of water, but it costs only $1 to produce, so Ernie has producer surplus of $3. He also receives $4 for his second bottle of water, which costs

19、 $3 to produce, so he has producer surplus of $1. Thus Ernies total producer surplus is $3 + $1 = $4, which is the area of A in the figure.c. When the price of a bottle of water rises from $4 to $6, Ernie sells three bottles of water, an increase of one. His producer surplus consists of both areas A

20、 and B in the figure, an increase by the amount of area B. He gets producer surplus of $5 from the first bottle ($6 price minus $1 cost), $3 from the second bottle ($6 price minus $3 cost), and $1 from the third bottle ($6 price minus $5 price), for a total producer surplus of $9. Thus producer surp

21、lus rises by $5 (which is the size of area B) when the price of a bottle of water rises from $4 to $6.5. a. From Ernies supply schedule and Berts demand schedule, the quantity demanded and supplied are:PriceQuantity SuppliedQuantity Demanded $ 213422631Only a price of $4 brings supply and demand int

22、o equilibrium, with an equilibrium quantity of 2.b. At a price of $4, consumer surplus is $4 and producer surplus is $4, as shown in problems 3 and 4. Total surplus is $4 + $4 = $8.c. If Ernie produced one fewer bottle, his producer surplus would decline to $3, as shown in problem 4. If Bert consume

23、d one fewer bottle, his consumer surplus would decline to $3, as shown in problem 3. So total surplus would decline to $3 + $3 = $6.d. If Ernie produced one additional bottle of water, his cost would be $5, but the price is only $4, so his producer surplus would decline by $1. If Bert consumed one a

24、dditional bottle of water, his value would be $3, but the price is $4, so his consumer surplus would decline by $1. So total surplus declines by $1 + $1 = $2.6. a. The effect of falling production costs in the market for stereos results in a shift to the right in the supply curve, as shown in Figure

25、 11. As a result, the equilibrium price of stereos declines and the equilibrium quantity increases.b. The decline in the price of stereos increases consumer surplus from area A to A + B + C + D, an increase in the amount B + C + D. Prior to the shift in supply, producer surplus was areas B + E (the

26、area above the supply curve and below the price). After the shift in supply, producer surplus is areas E + F + G. So producer surplus changes by the amount F + G B, which may be positive or negative. The increase in quantity increases producer surplus, while the decline in the price reduces producer

27、 surplus. Since consumer surplus rises by B + C + D and producer surplus rises by F + G B, total surplus rises by C + D + F + G.c. If the supply of stereos is very elastic, then the shift of the supply curve benefits consumers most. To take the most dramatic case, suppose the supply curve were horiz

28、ontal, as shown in Figure 12. Then there is no producer surplus at all. Consumers capture all the benefits of falling production costs, with consumer surplus rising from area A to area A + B.Figure 11Figure 127. Figure 13 shows supply and demand curves for haircuts. Supply equals demand at a quantit

29、y of three haircuts and a price between $4 and $5. Firms A, C, and D should cut the hair of Riki, Jerry, and Montel. Oprahs willingness to pay is too low and firm Bs costs are too high, so they do not participate. The maximum total surplus is the area between the demand and supply curves, which tota

30、ls $11 ($8 value minus $2 cost for the first haircut, plus $7 value minus $3 cost for the second, plus $5 value minus $4 cost for the third).Figure 138. a. The effect of falling production costs in the market for computers results in a shift to the right in the supply curve, as shown in Figure 14. A

31、s a result, the equilibrium price of computers declines and the equilibrium quantity increases. The decline in the price of computers increases consumer surplus from area A to A + B + C + D, an increase in the amount B + C + D.Figure 14 Prior to the shift in supply, producer surplus was areas B + E

32、(the area above the supply curve and below the price). After the shift in supply, producer surplus is areas E + F + G. So producer surplus changes by the amount F + G B, which may be positive or negative. The increase in quantity increases producer surplus, while the decline in the price reduces producer surplus. Since consumer surplus rises by B + C + D and producer surplus rises by F + G B, total surplus rises by C + D + F + G.Figure 15 b. Since