The formula for calculating simple interest is:
\[ \text{Simple Interest} = P \times r \times t \]
where:
- \( P \) is the principal amount (the initial amount of money),
- \( r \) is the annual interest rate (expressed as a decimal), and
- \( t \) is the time (in years) that the money is invested or borrowed.
To calculate the total amount (A) after the interest has been applied, you can use the formula:
\[ A = P + \text{Simple Interest} \]
or simply:
\[ A = P \times (1 + r \times t) \]