Harry Taylor plans to pay an ordinary annuity of ​$6 comma 400 annually for ten years so he can take a​ year's sabbatical to study for a​ master's degree in business. The annual rate of interest is 3.1​%. How much will Harry have at the end of three​ years? How much interest will he earn on the investment after three​ years?

1 answer

To calculate how much Harry Taylor will have at the end of three years from his annuity payments, we first need to determine the future value of the ordinary annuity at the specified interest rate.

Step 1: Calculate the Future Value of the Annuity After 3 Years

The formula for the future value of an ordinary annuity is given by:

\[ FV = P \times \frac{(1 + r)^n - 1}{r} \]

Where:

  • \( FV \) = Future Value of the annuity
  • \( P \) = Payment per period
  • \( r \) = Interest rate per period
  • \( n \) = Total number of payments

In this case:

  • \( P = 6,400 \)
  • \( r = \frac{3.1}{100} = 0.031 \) (annual interest rate)
  • \( n = 3 \) (since we are only looking at the first three years)

Now, plug in the values:

\[ FV = 6,400 \times \frac{(1 + 0.031)^3 - 1}{0.031} \]

Calculating \((1 + 0.031)^3\):

\[ (1 + 0.031)^3 = (1.031)^3 \approx 1.09686 \]

Now, substituting this back into the formula:

\[ FV = 6,400 \times \frac{1.09686 - 1}{0.031} \] \[ FV = 6,400 \times \frac{0.09686}{0.031} \approx 6,400 \times 3.12806 \approx 19,998.88 \]

Thus, the total amount Harry will have at the end of three years is approximately $19,998.88.

Step 2: Calculate the Total Contributions

Now, let's calculate how much he actually contributed to the annuity over these three years:

\[ Total , Contributions = P \times n = 6,400 \times 3 = 19,200 \]

Step 3: Calculate Total Interest Earned

Now, to find out how much interest he earns, we subtract the total contributions from the future value:

\[ \text{Interest Earned} = FV - \text{Total Contributions} \] \[ = 19,998.88 - 19,200 = 798.88 \]

Final Results:

  • At the end of three years, Harry will have approximately $19,998.88.
  • The total interest earned on the investment after three years will be approximately $798.88.