国际经济学克鲁格曼教材答案

Chapter 3

1．Home has 1200 units of labor available. It can produce two goods, apples

and bananas. The unit labor requirement in apple production is 3, while

in banana production it is 2.

a．Graph out the production possibilities frontier:

b．What is the opportunity cost of apples in terms of bananas? c．In the absence of trade, what would the price of apples in terms of

bananas be?

In the absence of trade, since labor is the only factor of production

and supply decisions are determined by the attempts of individuals to

maximize their earnings in a competitive economy, only when

will both goods be produced. So 1.5? P/P ?P/P a/a bLbaaLab2．Home is as described in problem 1. There is now also another country, Foreign, with a labor force of 800. Foreign's unit labor requirement in apple production is 5, while in banana production it is 1. a．Graph Foreign's production possibilities frontier:

Foreign's PPFQ*banana Construct the world relative supply curve. b．1000800Now suppose world relative demand takes the following form: Demand for ．3600400apples/demand for bananas = price of

bananas/price of apples. 2000along

the curve relative Graph asupply ．the demand with relative curve: Q*40032024016080apple

∵When the market achieves its equilibrium,we have

?PQ D Q?a?1a a a)(???P D QQ?bb b b1 RD is a hyperbola ∴?y x b．What is the equilibrium relative price of apples?

The equilibrium relative price of apples is determined by the intersection of the RD and RS curves.

1 RD: ?x yx?[0,0.5)y?1.5?? RS: ],551.5y?[x?0.??y???5,]5x?(0.?∴2?.5yx?0ee∴2P?bPa/c．Describe the pattern of trade.

??ee∵P/PP?/P?PP/baabba∴In this two-country world, Home will specialize in the apple

production, export apples and import bananas. Foreign will

specialize

in the banana production, export bananas and import apples. d．Show that both Home and Foreign gain from trade.

International trade allows Home and Foreign to consume anywhere within

the colored lines, which lie outside the countries' production possibility frontiers. And the indirect method, specializing in more

a is country, other with trade then production one only producing efficient method than direct production. In the absence of trade, Home

could gain three bananas by foregoing two apples, and Foreign could gain by one foregoing five bananas. Trade allows each country to trade

two bananas for one apple. Home could then gain four bananas by foregoing two apples while Foreign could gain one apple by foregoing only two bananas. So both Home and Foreign gain from trade. 4．Suppose that instead of 1200 workers, Home had 2400. Find the equilibrium

relative price. What can you say about the efficiency of world production

and the division of the gains from trade between Home and Foreign