An amount of money is invested at 12%/a interest. Write an equation and solve it to determine the length of time it will take for the original amouunt to double if the interest is compounded annually.
math - MathMate, Thursday, December 3, 2009 at 10:33pm
The rule of 72 gives the rough period as 72/12=6 years.
The accurate calculation is as follows:
R=interest rate= 1.12 for 12%
n=number of years required.
Take log on both sides,
n*log(R) = log(2)