Final answer:
To provide a retirement annuity, the sum needed at retirement is calculated using the present value of annuity formula, while the annual deposits during the accumulation period are determined using the future value of annuity formula. Changes in the interest rate and terms of the annuity, such as a perpetuity, will affect the annual deposit amounts required.
Step-by-step explanation:
The question involves calculating the fund's accumulation to provide a retirement annuity and determining the annual deposits needed during the accumulation period. To solve this problem, one requires an understanding of present value (PV) and future value (FV) concepts in finance, particularly as they relate to annuities and the effect of compound interest.
To calculate the sum needed by the end of year 12 to provide the 20-year, $42,000 annuity at a 12% interest rate, we calculate the present value of an annuity:
- PV = Pmt [((1-(1+r)^-n)/r)]
To calculate the required end-of-year deposits, we apply the future value of an annuity formula:
If the interest rate during the accumulation period is 10%, the annual deposit would change because a higher interest rate allows for a smaller deposit to reach the same future value. If the retirement annuity is a perpetuity, the formula simplifies to PV = Pmt / r because perpetuities have no end.
Understanding these principles is necessary to provide sufficient retirement savings and engage in effective financial planning.