From 2006 to 2010,per capita real gross domestic product (GDP)in Ethiopia grew an average of 7.99% per year.At that rate,according to the Rule of 70,in roughly how many years will the Ethiopian economy double in size?

Question

Quizplus · Accepted Answer

The Rule of 70 states that the number of years it takes for a variable to double is approximately equal to 70 divided by the annual growth rate of the variable. 
In this case, the annual growth rate of per capita real GDP in Ethiopia is 7.99%, so we can calculate:
70 / 7.99 = 8.76 (rounded to 8.8 years)
Therefore, it would take approximately 8.8 years for the Ethiopian economy to double in size at this growth rate. Thus, the correct choice is C) 8.8 years.

From 2006 to 2010,per Capita Real Gross Domestic Product (GDP)in