Joint probability is the probability of two events happening together.
The two events are usually designated event A and event B. In probability terminology, it can be written as:
Anyway, if an event A and B are idenpendent then , and therefore, become
Example: The probability that a card is a five and black = p(five and black)
2/52 = 1/26
(There are two black fives in a deck of 52 cards, the five of spades and the five of clubs).