Why do we use probability?

Hint: Probability is the state of being probable and the extent to which something is likely to happen in the particular situations or the favourable outcomes. Probability of any given event is equal to the ratio of the favourable outcomes with the total number of the outcomes.
$P(A) = $ Total number of the favourable outcomes / Total number of the outcomes

Complete answer:
The concept of probability is very important and it plays the vital role to have an understanding of the nature of chance and the variation in life.
The probability helps estimates and the predictions from an important part of research investigation. It is used in almost every field and used by mathematician, economist, market research analyst, budget analyst, atmospheric scientist, statistician, operations research analyst and financial analyst which gives the data which can be categorized as the favorable and unfavorable ones.
It also helps to understand the risk and take decisions accordingly.
For example: Probability is used in gambling.
Other Examples include:
I.Batting average in cricket
II. Lottery tickets
III.Playing cards
IV.Flipping a Dice or coin
V.Weather forecasting

Note: The probability of any event always ranges between zero and one. It can never be the negative number or the number greater than one. The probability of impossible events is always equal to zero whereas, the probability of the sure event is always equal to one. The concepts of the probability are extremely important to understand the risk and relative risk which ultimately helps to predict and take decisions.