A convenient rule of thumb called the "rule of 72" states that a quantity growing at x percent per year doubles in size approximately every (72/x) years.
-Refer to the information above.If an economy can raise its annual real GDP growth rate from 1.8 percent to 2.4 percent,its real GDP doubling time is reduced by ________ years.
A)30
B)24
C)10
D)43.2

Question

Quizplus · Accepted Answer

Using the rule of 72, at 1.8% growth, doubling time = 72 / 1.8 = 40 years. At 2.4% growth, doubling time = 72 / 2.4 = 30 years. The reduction in doubling time is 40 - 30 = 10 years.

A Convenient Rule of Thumb Called the "Rule of 72