A deposit of 1200 is made into each of two back accounts. No additional deposits or withdrawals will be made for 4 years.

Account 1 earns 1.5% annual simple interest
Account 2 earns 1.5% interest compounded annually.

Whats the difference between the 2 accounts at the end of 4 years?

1 answer

To find the difference between the two accounts at the end of 4 years, we'll calculate the total amount in each account and then determine the difference.

Account 1: Simple Interest

The formula for simple interest is:

\[ A = P(1 + rt) \]

Where:

  • \(A\) is the total amount after time \(t\),
  • \(P\) is the principal amount (initial deposit),
  • \(r\) is the annual interest rate (as a decimal),
  • \(t\) is the time in years.

For Account 1:

  • \(P = 1200\)
  • \(r = 0.015\) (1.5% as a decimal)
  • \(t = 4\)

Plugging the values into the formula:

\[ A_1 = 1200(1 + 0.015 \times 4) \] \[ A_1 = 1200(1 + 0.06) \] \[ A_1 = 1200 \times 1.06 \] \[ A_1 = 1272 \]

Account 2: Compounded Interest

The formula for compound interest is:

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

For Account 2:

  • \(P = 1200\)
  • \(r = 0.015\)
  • \(t = 4\)

Plugging the values into the formula:

\[ A_2 = 1200(1 + 0.015)^4 \] \[ A_2 = 1200(1.015)^4 \]

Calculating \(1.015^4\):

\[ 1.015^4 \approx 1.061364 \]

Now plugging this value back into the equation:

\[ A_2 \approx 1200 \times 1.061364 \] \[ A_2 \approx 1273.64 \]

Difference Between the Accounts

Now we find the difference between Account 2 and Account 1:

\[ \text{Difference} = A_2 - A_1 \approx 1273.64 - 1272 = 1.64 \]

Thus, the difference between the two accounts at the end of 4 years is approximately $1.64.