In many simple interest problems you will be finding the total interest earned over a set period which is represented as I. Using the Simple Interest Formula 1. Get your calculator and check to see if youre right.
Interest I Principal P times Rate Per Period r times Number of Periods n Divide an annual rate by 12 to get r if the Period is a month.
I Prt becomes r IPt Remember to use 1412 for time and move the 12 to the numerator in the formula above. Interest rates are typically expressed as a percentage. This math video tutorial explains how to use the simple interest formula to solve word problems. Convert the interest rate to a decimal value.