To find the final amount in the retirement account after 12 years with changing rates of return and contributions, we need to calculate the future value of the account step by step:
1. **First 6 years:**
- $257 per month is invested at a 4% annual interest rate, compounded monthly for 6 years.
- Using the future value of an ordinary annuity formula:
- Future Value = Pmt * [(1 + r/n)^nt - 1] / (r/n)
- Pmt = $257, r = 4% or 0.04, n = 12 (monthly compounding), t = 6 years
- Calculate the future value for this period.
2. **Next 6 years:**
- $385 per month is invested at a 6% annual interest rate, compounded monthly for 6 years.
- Repeat the calculation using the new parameters:
- Pmt = $385, r = 6% or 0.06, n = 12, t = 6 years
- Calculate the future value for this period.
3. **Total amount after 12 years:**
- Add the future values calculated in step 1 and step 2 to find the total amount in the account after 12 years.
By following these steps, you can determine the final amount in the retirement account after 12 years with changing rates of return and contributions.