Brooke opens a credit card with an APR of 28.99%. how much is charged in interest this month if her balance is $500?

To find the interest accrued for the month, you will use the interest formula I = prt. P stands for the principal (the amount of money borrowed), r is the interest rate, and t is the time period. Because the interest rate is an annual (yearly) interest rate, you will use the fraction 1/12 in your calculation. The math would be $500 x 0.2899 x 1/12. This equals an interest charge of $12.08.