Sally will discharge a debt of R50 000 6 years from now, using the sinking method fund. The debt's interest is 15.6% per year, paid quarterly. The sinking fund earns interest at a rate of 8.4% per year, compounded monthly. (a) What is the monthly deposit into the sinking fund? (b) What is the total yearly cost to discharge the debt (to the nearest rand) ? Please show calculations