1. **Problem statement:** Louis saves 250 each month for 30 years in an account with an annual interest rate of 4.55%. We want to find the total amount in his account at retirement. 2. **Formula used:** This is a future value of an ordinary annuity problem. The formula is: $$FV = P \times \frac{(1 + r)^n - 1}{r}$$ where: - $P$ is the monthly payment - $r$ is the monthly interest rate - $n$ is the total number of payments 3. **Calculate monthly interest rate:** Annual rate = 4.55% = 0.0455 Monthly rate $r = \frac{0.0455}{12} = 0.0037917$ 4. **Calculate total number of payments:** $30$ years $\times 12$ months/year $= 360$ payments 5. **Plug values into formula:** $$FV = 250 \times \frac{(1 + 0.0037917)^{360} - 1}{0.0037917}$$ 6. **Calculate $(1 + 0.0037917)^{360}$:** $$ (1.0037917)^{360} \approx 3.877 $$ 7. **Calculate numerator:** $$3.877 - 1 = 2.877$$ 8. **Calculate fraction:** $$\frac{2.877}{0.0037917} \approx 758.9$$ 9. **Calculate future value:** $$FV = 250 \times 758.9 = 189,725$$ **Answer:** Louis will have approximately 189,725 in his retirement account after 30 years.