Chapter 18/Open-Economy Macroeconomics: Basic Concepts ❖ 309
3. Suppose that
P
is the price of a basket of goods in the United States (measured in dollars),
P*
is the price of a basket of goods in Japan (measured in yen), and
e
is the nominal
exchange rate (the number of yen each dollar can buy).
a. In the United States, the purchasing power of $1 is 1/
P
.
d. Rearranging, we get:
Note that the left-hand side is a constant and the right-hand side is the
real exchange rate. This implies that if the purchasing power of a dollar
is always the same at home and abroad, then the real exchange rate
cannot change.
e. We can rearrange again to see that:
The nominal exchange rate is determined by the ratio of the foreign
price level to the domestic price level. Nominal exchange rates will
change when price levels change.
4. Because the nominal exchange rate depends on the price levels, it must also depend on the
money supply and money demand in each country.
a. If the central bank increases the supply of money in a country and raises the price level,
it also causes the country’s currency to depreciate relative to other currencies in the
world.
5.
Case Study: The Nominal Exchange Rate during a Hyperinflation
a. Figure 3 shows the German money supply, the German price level, and the nominal
exchange rate (measured as U.S. cents per German mark) during Germany’s
hyperinflation in the early 1920s.
b. When the supply of money begins growing, the price level also increases and the
German mark depreciates.
D. Limitations of Purchasing-Power Parity