To calculate James's monthly instalment, we can use the formula for the monthly payment on an amortizing loan:

$M = \frac{P \times r \times (1 + r)^n}{(1 + r)^n - 1}$

Where:

• $M$ is the monthly payment.
• $P$ is the principal amount (R140,000).
• $r$ is the monthly interest rate (annual interest rate divided by 12).
• $n$ is the total number of payments (50 months).

Let's plug in the values:

• $P = 140,000$ Rands
• Annual interest rate = 12%, so monthly interest rate $r = \frac{12\%}{12} = 0.01$
• $n = 50$ months

Now, we'll calculate the monthly payment $M$.James's monthly instalment would be approximately R3,571.78.

Would you like more details or have any other questions? Here are some related questions you might consider:

1. How does the interest rate impact the monthly payment?
2. What would happen if James chose a shorter repayment period, like 36 months?
3. How much total interest will James pay over the 50 months?
4. What is the formula for calculating the total cost of the loan?
5. How does the compound interest formula differ from the simple interest formula?

Tip: When dealing with loans, understanding the difference between simple and compound interest is crucial, as compound interest can significantly increase the total amount you repay.