9 years ago your grandfather put $55,000 in an account that paid 4.8% compounded monthly. 7 years later he moved all the money into mutual funds. Over the next 2 years the mutual funds dropped in value by 10% from the value at the end of year 10. What effective rate of return did he average over the 12 years?

i = interest, FV = future value, PV = pres. value

Formulas: FV = PV (1+i)^n

PV = FV/(1+i)^n or PV = FV (1+i)^-n