
Answers to Textbook Problems
1. We saw that not only is GDP important in explaining how much two countries trade, but also,
2. Mexico is quite close to the United States, but it is far from the European Union (EU), so it makes sense
3. No, if every country’s GDP were to double, world trade would not quadruple. Consider a simple
example with only two countries: A and B. Let country A have a GDP of $6 trillion and B have a
GDP of $4 trillion. Furthermore, the share of world spending on each country’s production is
proportional to each country’s share of world GDP (stated differently, the exponents on GDP in
Equation 2-2, a and b, are both equal to 1). Thus, our example is characterized by the table below:
Country GDP Share of World Spending
What happens if we double GDP in both countries? Now GDP in country A is $12 trillion and GDP in
country B is $8 trillion. However, the share of world income (and spending) in each country has not
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