At what interest rate, compunded annually will an amount of money double itself in 12 years?

Question

At what interest rate, compunded annually will an amount of money double itself in 12 years?

Answer 1

The amount at interest rate i, for n years is A=A₀(1+i)ⁿ Now the question is for what i will A=2*A₀ when n=12 years.so

 

2=(1+i)¹² taking log of both sides ln (2) = 12*ln(1+i) so 1+i=e^.05776 -1,  and i=.0594 or 5.9%/year

 

Jim