Question $3$: $15$ Marks

Your parents are considering a $40-$year, R$200,000$ mortgage that charges $0\mathrm{.}7\%$ interest each month. Formulate a model in terms of a monthly repayment $W$ that allows the mortgage $($loan$)$ to be paid off after $n$ repayments. Use a suitable model to determine the monthly repayment $W.$