3. A grandmother wants to provide an annuity of $3000 payable at the end of every six months during the three years that her grandson attends college. What single deposit ut she make today that will finance the annuity, if the grandson will start college in 15 years? Assume she can invest the money at 2.85% compounded semi-annually for the first seven years, and then at 3.0% compounded semi-annually for the next 11 years