Loan Initial Amount
1. **State the problem:**
Jimmy pays R3876.90 monthly towards a 12-year home loan with an annual interest rate of 11.75% compounded monthly. We need to find the initial loan amount.
2. **Identify known values:**
- Monthly payment, $P = 3876.90$
- Annual interest rate, $r = 11.75\% = 0.1175$
- Number of years, $t = 12$
- Compounding frequency: monthly, so number of payments, $n = 12 \times 12 = 144$
- Monthly interest rate, $i = \frac{0.1175}{12} = 0.00979167$
3. **Relevant formula:**
The formula for the present value (initial loan) of an annuity (loan payments) is:
$$
L = P \times \frac{1 - (1+i)^{-n}}{i}
$$
where $L$ is the loan amount, $P$ payment per period, $i$ interest rate per period, and $n$ total payments.
4. **Calculate**:
Calculate $(1+i)^{-n}$:
$$
(1 + 0.00979167)^{-144} = (1.00979167)^{-144}
$$
Calculate this value first:
$$
(1.00979167)^{144} = e^{144 \times \ln(1.00979167)} \approx e^{144 \times 0.009745} = e^{1.402} \approx 4.064
$$
Therefore,
$$
(1.00979167)^{-144} = \frac{1}{4.064} \approx 0.2462
$$
5. Substitute in formula:
$$
L = 3876.90 \times \frac{1 - 0.2462}{0.00979167} = 3876.90 \times \frac{0.7538}{0.00979167}
$$
Calculate denominator:
$$
\frac{0.7538}{0.00979167} \approx 76.987
$$
Multiply:
$$
L = 3876.90 \times 76.987 \approx 298548.45
$$
**Final answer:**
Jimmy's initial loan amount was approximately R298548.45.