Etymologically the word interest comes from the Latin term “interested” and it is related to what is found between people attracting them, captivating them so that there is an inclination towards it.

Many times people relate to others through a certain interest, when some personal benefit is sought, interest can arise in people when something can cause them a benefit, a curiosity, a learning, when a person watches a movie or reads a book is because it causes interest, because the topic addressed in them, are current issues or that in some way generates influence in their personal and social life.

In the field of economics, interest refers to an index used to measure the profitability of investments or bank savings. Depending on the amount invested or saved, the interest rate will show the percentage that will be obtained as a benefit, if the interest is related to an acquired loan, in this case it will indicate the percentage that must be canceled. There are two types of interest: fixed interest, which is the one that is used in different financial transactions, this type of interest implies the calculation of a single percentage on the capital for the entire duration of the loan or deposit.

The variable interest, is the one that is calculated on the capital and that varies or modifies over time, this kind of interest is applied in each period of time and is comprised of two figures, which result from the addition of both : a reference index and a differential percentage.