When Martin was born, his father set up a $5,000 college fund for him with an annual compound interest rate of 7.3%. What is the total value of this account after 18 years, and what was the interest earned on the account? Round the answers to two decimal places. *Remember to use your STAAR Reference Sheet for support! (2 points) The final amount of the college fund is $ , and the amount of interest earned on the account is $ .

1 answer

To calculate the total value of the college fund after 18 years with an initial amount of $5,000 and an annual compound interest rate of 7.3%, we can use the formula for compound interest:

\[ A = P(1 + r)^n \]

Where:

  • \( A \) = the amount of money accumulated after n years, including interest.
  • \( P \) = the principal amount (the initial amount of money).
  • \( r \) = annual interest rate (decimal).
  • \( n \) = number of years the money is invested for.

Given:

  • \( P = 5000 \)
  • \( r = 7.3% = 0.073 \)
  • \( n = 18 \)

Substituting in the values:

\[ A = 5000(1 + 0.073)^{18} \] \[ A = 5000(1.073)^{18} \]

Next, we calculate \( (1.073)^{18} \):

\[ (1.073)^{18} \approx 3.67932 \quad (\text{using a calculator}) \]

Now, substituting this back into the formula:

\[ A \approx 5000 \times 3.67932 \approx 18396.60 \]

Thus, the total amount in the college fund after 18 years is approximately \( A = 18396.60 \).

To find the interest earned on the account, we subtract the initial principal from the total amount:

\[ \text{Interest} = A - P \] \[ \text{Interest} = 18396.60 - 5000 = 13396.60 \]

Therefore, the final values rounded to two decimal places are:

  • The final amount of the college fund is $18,396.60.
  • The amount of interest earned on the account is $13,396.60.