We are going to put $2500 into an account that earns interest at a rate of 12%. If we w ant to have $4000 in the account when we close it how long should we keep the money in the account if, we compound interest continuously. We compound interest 6 times a year. Solution For compounded interest continuously , the formula of amount is A= Pert Where A= amount, P=Principal, r= rate of interest and t=time period Here Amount ,A= $4000, Principal,P=$2500, Rate of interest,r=12% Substituting these values in the formula 4000=2500e0.12t Dividing both sides by 2500 4000/2500=2500e0.12t/2500 1.6= e0.12t Taking Ln on both sides Ln 1.6=Ln e0.12t .47=0.12t Dividing both sides by 0.12 .47/0.12=0.12t/0.12 3.92=t Or time,t=3.92.