4. The City Board of Education borrowed $750 000 for 20 years at 13% compounded annually to finance construction of Hillview Elementary School. The board created a sinking fund to repay the debt at the end of 20 years. Equal payments are made into the sinking fund at the end of each year, and interest earned by the fund is 10.5% compounded annually. Rounding all computations to the nearest dollar, i determine the annual cost of the debt; ii. compute the book value of the debt at the end of 10 years