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? (1) R4236.10 (2) R5364.60 (3) R10736.10 (4) R12958.53 (5) R16235.96 (b) What is the total yearly cost to discharge the debt (to the nearest rand) ? (1) R42000 (2) R78000 (3) R93834 (4) R128833 (5) R142375 Please show calculations