You have determined that you will need N$200 000 per year for four years to send your daughter to university in South Africa. You have already saved N$40 000, and you have placed the money in an account that you expect will yield a monthly compounded interest rate of 0.75%. Money for the first of the four payments will be removed from the account exactly 15 years from now, and the last withdrawal will be made 18 years from now. You have decided to save more by making monthly payments into the same account, yielding 0.75% interest per month over the next 14 years beginning next month. You will take the money out of the 0.75% per month account and place it in a 6% per annum account in 14 years and take the cash out as needed. Required: How much money should you invest monthly to achieve this goal? Please provide detailed workings and commentaries explaining why you make certain assumptions and why you take certain actions, backed with appropriate academic sources.