If an economy's GDP will double in 25 years, then its growth rate must be about

Question

Quizplus · Accepted Answer

The rule of 70 states that to estimate the number of years it takes for a variable to double, we divide the number 70 by the annual growth rate of that variable. In this case, since the GDP is expected to double in 25 years, we can use the rule of 70 to calculate the annual growth rate: 
70 / Annual growth rate = 25
Annual growth rate = 70 / 25 
Annual growth rate = 2.8%
Therefore, the correct answer is B) 2.8%.

If an Economy's GDP Will Double in 25 Years, Then