Education Insurance E7D9Ee
1. **Problem Statement:** Suzana has two options for her education fund of 26,442. Option 1: Invest 26,442 at 4.25% interest compounded monthly and withdraw equal monthly payments for 4 years. Option 2: Receive 560 every month for 4 years from her parents.
2. **Formula for Option 1 (Annuity Withdrawal):**
The formula for the monthly payment $P$ from a principal $PV$ with monthly interest rate $i$ over $n$ months is:
$$P = PV \times \frac{i(1+i)^n}{(1+i)^n - 1}$$
3. **Calculate parameters:**
- Annual interest rate $r = 4.25\% = 0.0425$
- Monthly interest rate $i = \frac{0.0425}{12} = 0.0035417$
- Number of months $n = 4 \times 12 = 48$
- Principal $PV = 26,442$
4. **Calculate monthly payment for Option 1:**
$$P = 26,442 \times \frac{0.0035417(1+0.0035417)^{48}}{(1+0.0035417)^{48} - 1}$$
Calculate $(1+0.0035417)^{48} \approx 1.1855$
$$P = 26,442 \times \frac{0.0035417 \times 1.1855}{1.1855 - 1} = 26,442 \times \frac{0.004198}{0.1855} = 26,442 \times 0.02263 = 598.6$$
So, monthly payment from investment is approximately 598.6.
5. **Compare with Option 2:** Parents give 560 monthly.
6. **Conclusion:** Since 598.6 > 560, Option 1 yields more monthly money. Suzana should choose Option 1.
---
7. **Problem b:** Laptop cost 3,250 with 10% down payment and 3.5% interest compounded monthly over 36 months.
8. **Calculate down payment:**
$$\text{Down payment} = 0.10 \times 3,250 = 325$$
9. **Loan amount:**
$$PV = 3,250 - 325 = 2,925$$
10. **Monthly interest rate:**
$$i = \frac{3.5\%}{12} = 0.0029167$$
11. **Number of payments:**
$$n = 36$$
12. **Monthly payment formula:**
$$P = PV \times \frac{i(1+i)^n}{(1+i)^n - 1}$$
Calculate $(1+0.0029167)^{36} \approx 1.1097$
$$P = 2,925 \times \frac{0.0029167 \times 1.1097}{1.1097 - 1} = 2,925 \times \frac{0.003236}{0.1097} = 2,925 \times 0.02952 = 86.3$$
Monthly payment is approximately 86.3.
13. **Total payment:**
$$86.3 \times 36 = 3,106.8$$
14. **Interest charged:**
$$3,106.8 - 2,925 = 181.8$$
---
15. **Problem c i):** After 30 payments, find remaining balance.
16. **Remaining balance formula:**
$$B = P \times \frac{1 - (1+i)^{-(n-k)}}{i}$$
where $k=30$ payments made.
Calculate $(1+i)^{-(n-k)} = (1.0029167)^{-6} \approx 0.9827$
$$B = 86.3 \times \frac{1 - 0.9827}{0.0029167} = 86.3 \times \frac{0.0173}{0.0029167} = 86.3 \times 5.93 = 511.5$$
Additional payment to settle loan immediately is approximately 511.5.
17. **Problem c ii):** Total interest paid if settled after 30 payments plus additional payment.
Total paid = (30 payments \times 86.3) + 511.5 = 2,589 + 511.5 = 3,100.5
Interest paid = 3,100.5 - 2,925 = 175.5
---
18. **Problem d:** Missed first 4 payments, pay all arrears on 5th payment.
19. **Calculate arrears with interest:**
Each missed payment accrues interest for months until 5th payment.
- 1st missed payment: 4 months interest
- 2nd missed payment: 3 months interest
- 3rd missed payment: 2 months interest
- 4th missed payment: 1 month interest
Calculate future value of each missed payment $P=86.3$:
$$FV = P \times (1+i)^m$$
Sum:
$$86.3 \times (1.0029167^4 + 1.0029167^3 + 1.0029167^2 + 1.0029167^1)$$
Calculate powers:
$$1.0117 + 1.0087 + 1.0058 + 1.0029 = 4.0291$$
Total arrears:
$$86.3 \times 4.0291 = 347.7$$
20. **Add 5th payment:**
$$86.3 + 347.7 = 434.0$$
Suzana's father should pay approximately 434.0 on the 5th payment to settle all arrears.
**Final answers:**
- a) Choose Option 1 with monthly payment 598.6
- b) Monthly payment 86.3, interest charged 181.8
- c i) Additional payment 511.5
- c ii) Total interest paid 175.5
- d) Payment on 5th month to settle arrears 434.0