Present Value Annuity
1. **State the problem:** Alexandra wants to find the present amount to deposit today to allow withdrawals of 1149 at the beginning of every 3 months for 2 years, with an interest rate of 3.20% compounded semi-annually.
2. **Identify the type of problem:** This is a present value of an annuity due problem because withdrawals happen at the beginning of each period.
3. **Given data:**
- Payment per period, $R = 1149$
- Number of years, $t = 2$
- Payments every 3 months, so number of payments per year $= 4$
- Total number of payments, $n = 4 \times 2 = 8$
- Annual nominal interest rate, $i_{nom} = 3.20\% = 0.032$
- Compounded semi-annually means 2 compounding periods per year.
4. **Find the effective interest rate per payment period:**
- Semi-annual interest rate $= \frac{0.032}{2} = 0.016$
- Since payments are quarterly (every 3 months), but compounding is semi-annual (every 6 months), we need the effective quarterly rate.
- Effective semi-annual factor: $1 + 0.016 = 1.016$
- Effective quarterly rate $i = \sqrt{1.016} - 1 = 1.016^{0.5} - 1 \approx 0.007968$
5. **Formula for present value of an annuity due:**
$$
PV = R \times \frac{1 - (1 + i)^{-n}}{i} \times (1 + i)
$$
6. **Calculate:**
- Calculate $(1 + i)^{-n} = (1.007968)^{-8} \approx 0.9385$
- Calculate numerator: $1 - 0.9385 = 0.0615$
- Divide by $i$: $\frac{0.0615}{0.007968} \approx 7.715$
- Multiply by $(1 + i)$: $7.715 \times 1.007968 \approx 7.777$
- Multiply by $R$: $7.777 \times 1149 \= 8933.37$
7. **Answer:** Alexandra should deposit approximately $8933.37$ today to provide the payments.
**Final answer:** $\boxed{8933.37}$