$50,000 is borrowed at a nominal annual rate of 6.4% compounded semi-annually. The term of the loan is 10 years. The loan may be repaid by either the standard amortization method or ny the sinking fund method. The payment with the amortiztion method is $y. If the loan is repaid by the sinking fund method the loan is to be repaid with a lump sum payment at the end of 10 years. In order to pay off the loan, semi annual interest payments of $1600 are made to the bank and additionally, a deposit of size $X is made at the end of each six month period into a sinking fund earning a nominal annual rate of 7% interest, compounded semi-annually. The total payment under the sinking fund method is Z=X+1600. Determine Y-Z. (A sinking fund is a secondary account where we deposit funds that will need to grow to equal the loan amount.)