PriceD1996S1996D1986S1986D1976S1976Quantity Figure 2.7 8. a.消费者将增加苹果需求,导致需求曲线外移动。均衡价格和销售量都将增加。 b.由于橙子具有替代性,苹果的需求曲线将外移,均衡价格和销售量都将增加。 c.产量的下降将导致供给曲线向内移动,均衡价格上升,销售量下降。
d.苹果采摘着的增加将使苹果生产成本下降,供给增加,均衡价格下降,销售量上升。
e.供给曲线将外移,均衡价格下降,销售量上升。
练习题
1.
a.
ED?QDQDP?QD??. ?PQD?PP6
P = 80, Ed=–0.4
P = 100, Ed=–0.56
b.
ES?QSQSP?QS??. ?PQS?PP
P = 80, Es=0.5
.
P = 100, Es=0.56
c.均衡价格和数量为$100 ,18 million.
d.价格定在80$,需求为20 million.,供给为16 million.,相差4 million.
2.
QS = 1,800 + 240P QD = 2,580 - 194P.
Q?D = (2,580 - 194P) + 200 = 2,780 - 194P
1,800 + 240P = 2,780 - 194P, or
434P = 980, or P* = $2.26 per bushel. QS = 1,800 + (240)(2.26) = 2,342 QD = 2,780 - (194)(2.26) = 2,342.
3. a.
100 - 5P = 50 + 5P, P = $500.
QD = 100 - (5)(5) = 75 QS = 50 + (5)(5) = 75.
7
租金在500美金时,750,000公寓可以被租掉。
当租金被控制在100美金时,供给量将达到550,000 (QS = 50 + (5)(100) = 550),比管制前减少了200,000。假设每个公寓可容纳一个三口之家,将有600,000离开城市。
Rent$1,00090080070060050040030020010020406080100Appartments(10,000抯)ExcessDemandDemandSupply Figure 2.3
b.
当租金达到900美金时,公寓的供给为50 + 5(9) = 95,or 950,000这将超过
均衡水平200,000。因此(0.5)(200,000) = 100,000 个公寓被新建。但是需求仅仅为550,000。
4. a.
由总需求 Q = 3,550 - 266P, 国内需求, Qd = 1,000 - 46P, ,得到出口需求Qe = 2,550 - 220P. 均衡价格:
3,550 - 266P - 1,800 + 240P, or
P = $3.46.
需求减少40%,因此总需求
QD = Qd + 0.6Qe = 1,000 - 46P + (0.6)(2,550 - 220P) = 2,530 - 178P. 均衡价格
1,800 + 240P = 2,530 - 178P, or
P = $1.75,
8
在这一价格,市场出清量为2,219 million bushels,总收益从$9.1 billion 降至 $3.9 billion.这将令大部分农民痛苦。
b.
3美金的价格下市场并不在均衡状态,Demand = 1000 - 46(3) = 862. Supply = 1800 + 240(3) = 2,520, 超额供给 2,520 - 862 = 1,658.政府必须购买这个多余产量来支持价格,花费$3(1.66 million) = $5.0 billion每年。
5. a.
QD = a - bP. ED??bQ* = 7.5 (均衡产量).
P*IFGJ. E = -0.4 (长期价格弹性), P* = 0.75 (均衡价格),
HQ*KD
?0.4??b0.75IF, or b = 4.
HK7.57.5 = a - (4)(0.75), or a = 10.5.
QD = 10.5 - 4P.
b.
)需求下降20%:
Q?D?0.810.5?4P?8.4?3.2P.
afaf8.4 - 3.2P = -4.5 + 16P, or
P = 0.672.
6. a.
D = 24.08 - 0.06P SC = 11.74 + 0.07P.
在没有OPEC组织下的供给
Sc = Q* = 13.
ES = 0.10 , P* = $18, ES = d(P*/Q*) , d = 0.07. 代入 d, Sc, , P, c = 11.74 and Sc = 11.74 + 0.07P.
同样的, 因为 QD = 23, ED = -b(P*/Q*) = -0.05, b = 0.06. 代入 b, QD = 23, , P = 18 23 = a - 0.06(18), a = 24.08. 因此 QD = 24.08 - 0.06P.
b.
9
D = 32.18 - 0.51P SC = 7.78 + 0.29P.
如上, ES = 0.4 , ED = -0.4: ES = d(P*/Q*) , ED = -b(P*/Q*), 0.4 = d(18/13) and -0.4 = -b(18/23).
所以 d = 0.29 , b = 0.51.
Sc = c + dP , QD = a - bP,
13 = c + (0.29)(18) , 23 = a - (0.51)(18).
So c = 7.78 , a = 32.18.
c.
减产60亿桶后:
Sc? = 4 + Sc = 11.74 + 4 + 0.07P = 15.74 + 0.07P ,S? = 4 + Sc = 11.78 + 0.29P.
15.74 + 0.07P = 24.08 - 0.06P,
短期中,P = $64.15;
11.78 + 0.29P = 32.18 - 0.51P,
长期中,P = $24.29
7. a.
供给: Q = 14 + 2PG + 0.25PO 需求: Q = -5PG + 3.75PO
需求交叉弹性为:
EGO?设需求函数为:
F?QIFPI. GJGJ?PQHKHKGGOG?QIF(收入为常量), 则GJ = e. 将它代入交叉弹性公式, EH?PKGO QG = a - bPG + ePO
POFP*I?eGJ, P* and
Q*KHOOG* 是均衡价格和产量. 我们知道 P* = $8 ,* = 20 百万立方英尺(Tcf). QG QGO解得 e,
1.5?e同样得, 供给方程可表示为:
8IFGJ, e = 3.75.
H20KQG = c + dPG + gPO,
10
平狄克微观经济学课后习题答案(中文)



