Problema Solution

how long does it take 2800 investment to double if its invested at 9% compound semiannually. round to the nearest tenth of a year.

Answer provided by our tutors

P = $2,800 the principal


r = 0.09 or 9% annual interest rate


m = 2 compounding period per year


i = r/m = 0.09/2 = 0.045 interest rate per period


t = years


n = t*m = 2t total number of compounding periods


A = 2P the future value (the amount in the account after t years)


A = P(1 + i)^n


2P = P(1 + i)^n


(1 + 0.045)^(2t) = 2

........


click here to see all the equation solution steps


........

t = 7.9 years


It take 7.9 years for the investment to double.