Theoretical probability

First of all let us understand what is theoretical probability,

The theoretical probability (also called classical probability) of an event E,
written as P(E), is defined as
where we assume that the outcomes of the experiment are equally likely.

We will briefly refer to theoretical probability as probability.

This definition of probability was given by Pierre Simon Laplace in 1795.

Probability theory had its origin in the 16th century when
an Italian physician and mathematician J.Cardan wrote the
first book on the subject, The Book on Games of Chance.
Since its inception, the study of probability has attracted
the attention of great mathematicians. James Bernoulli
(1654 – 1705), A. de Moivre (1667 – 1754), and
Pierre Simon Laplace are among those who made significant
contributions to this field. Laplace’s Theorie Analytique
des Probabilités, 1812, is considered to be the greatest
contribution by a single person to the theory of probability.
In recent years, probability has been used extensively in
many areas such as biology, economics, genetics, physics,
sociology etc.
Hope the above explanation helped you, now let me give you examples on probability.