How long does it take $3300 to be doubled if invested at 9% compounded simiannually. Round to the nearest tenth of a year

Question

Thank you for all the help on the problem.

Answer 1

2 = 1.045^2t

take natural logs of both sides

ln2 = 2tln(1.045)

t = .5ln2/ln1.045 = about .7.87

= 7.9. years rounded to one decimal place

for compounding twice a year = doubling time at 9 percent annual interest rate

the doubling time is the same regardless of how much you start with