3. a) An investor pays 400 every half-year in advance into a 25-year savings plan. i) Calculate the accumulated fund at the end of the term if the interest rate is nominal 6% per annum convertible monthly for the first 15 years and nominal 6% per annum convertible half-yearly for the final 15 years. (5 marks] ii) Calculate the present value of the savings plan. (5 marks] b) An annuity with payments of 150 at the end of each quarter is to be replaced by an annuity with the same term and present value, but with payments at the beginning of each month. Calculate the revised payments, assuming an annual force of interest of 10%. (10 marks] (Total 20 marks]