I have a question that my professor gave me today where i have to find the rate of return the formula which i have to specifically use is R = (FV/PV)^1/n - 1 where R = rate of return which i have to find, Present Value = 100000000000, Future Value = 614,161,210,411 and number of years (n) = 20 according to me the answer is 9.5% however my professor says it should be a lower number for me. Any help is highly appreciated. Thank you in advance.