What is this amount of money called?

The correct answer to this question is interest. It is a payment from a borrower to a lender. Interest is more than the rate of the amount borrowed. Historian Paul Johnson dates this practice back to 5000 BC during Middle Easter civilizations, however the first written evidence is from 2400 BC. During this time, interest was used on agriculture.

Nowadays, interest is on loans, cars, and saving accounts. There are two times of interest rates, which are simple and compound interest. Simple interest is calculated by Principal x interest rate x n = interest. Compound interest is calculated by Principal x interest rate - interest for year one.