Question

Fourteen years ago william put money in his account at first national bank. william decides to cash in his account and is told that his money has quadrupled. according to the rule of 70, what rate of interest did alfred earn?
a. 5 percent
b. 10 percent
c. 14 percent
d. 7 percent

Answer 1

In the Rule of 70 you will get the length of time your money will double by dividing 70 by the growth rate. In here the money quadrupled after 14 years therefore it was doubled by its 7th year.  The rate can be computed as 70 divided by 7 and that is 10%. The answer is letter B.