dr. glock had an average balance of $400 on her credit card account for one year. She paid 1.75% interest per month. how much interest did she to pay altogether
The 400 comes from the average balance. 400(0.175) comes from the interest she has to pay each month. 1.75% as a decimal is 0.175. It's multiplied since she pays 1.75% of the average balance.