What interest rate would be necessary to obtain $6500 in 66 years if $5000 is the amount of the original investment and the interest is compounded yearly?
FV = PV[1 + R]^N
6,500 = 5,000[1 + R]^6 divide both sides by 5,000
1.3 = [1+R]^6 take the 6th root of both sides
1.3^(1/6) = 1 + R
1.0447 =1 + R subtract 1 from both sides
R =0.0447 x 100 = 4.47% the interest rate.
