Chapter 26 – An Introduction to Macroeconomics
26-8
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Answer: false.
As the time frame moves from a very short run to the long run prices will change from
being very sticky to flexible. Therefore, economists use 2 different models.
PROBLEMS
1. Suppose that the annual rates of growth of real GDP of Econoland over a five-year period were
sequentially as follows: 3 percent, 1 percent, -2 percent, 4 percent, and 5 percent. What was the
average of these growth rates in Econoland over these 5 years? What term would economists use
to describe what happened in year 3? If the growth rate in year 3 had been a positive 2 percent
rather than a negative 2 percent, what would have been the average growth rate? LO1
2. Suppose that Glitter Gulch, a gold mining firm, increased its sales revenues on newly mined
gold from $100 million to $200 million between one year and the next. Assuming that the price of
gold increased by 100 percent over the same period, by what numerical amount did Glitter
Gulch’s real output change? If the price of gold had not changed, what would have been the
change in Glitter Gulch’s real output? LO1
3. A mathematical approximation called the rule of 70 tells us that the number of years that it will
take something that is growing to double in size is approximately equal to the number 70 divided
by its percentage rate of growth. Thus, if Mexico’s real GDP per person is growing at 7 percent
per year, it will take about 10 years (= 70/ 7) to double. Apply the rule of 70 to solve the
following problem. Real GDP per person in Mexico in 2005 was about $11,000 per person, while
it was about $44,000 per person in the United States. If real GDP per person in Mexico grows at
the rate of 5 percent per year, about how long will it take Mexico’s real GDP per person to reach
the level that the United States was at in 2005? (Hint: How many times would Mexico’s 2005 real
GDP per person have to double to reach the United States’ 2005 real GDP per person?) LO2