A series of ten $500 payments are received at the end of each year over a 10-year period. During the first two years the interest rate was 5% annual compounded monthly. During the following two years (years 3-4) the interest rate was 6% annual compounded semiannually. During the last six years (years 5-10) the interest rate was 12% compounded annually. find the present equivalent of this series of payments.