I claim I can double your investment in two years. What monthly rate of return am I advertising? Solution FV = PV (1+r/n)*n*m where r= rate of interest m= period, i.e = monthly =12 n =years = 2year Let amount invested = X 2X = X(1+r/12)*24 2= (1+0.083333333) 1.0293 -1 = 0.0833 0.3517.