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.An economy's real GDP per person doubles every 18 years when it maintains a growth rate of ________ per year.
A)5.6 percent
B)4.0 percent
C)0.25 percent
D)0.9 percent

Question

Quizplus · Accepted Answer

Using the "rule of 72", we can find that the necessary growth rate is (72/18)= 4 percent. Therefore, the correct choice is B.

A Convenient Rule of Thumb Called the "Rule of 72