If your interest is per year then you have your balance and you multiply it by the interest rate. In this case your balance is 5270 and interest is 15.53%. This is calculated as 5270 * .1553 = 818.43 Then you take this value, which is the interest calculated, and add it to your original value. 5270 + 818.43 = $6088.43

It seems to give you your yearly interest, unless you have the number of years this is over.

I hope this helps a little. Please let me know if you have any questions.