Define mutually exclusive events.

Mutually exclusive events are events that cannot occur at the same time.

When two events are mutually exclusive, it means that they cannot happen simultaneously. For example, if we toss a coin, the event of getting a head and the event of getting a tail are mutually exclusive. It is impossible to get both a head and a tail at the same time. Similarly, if we roll a dice, the event of getting a 1 and the event of getting a 2 are mutually exclusive.

Mathematically, we can represent mutually exclusive events using the following formula:

P(A or B) = P(A) + P(B)

where P(A or B) is the probability of either event A or event B occurring, P(A) is the probability of event A occurring, and P(B) is the probability of event B occurring.

For example, if we roll a dice, the probability of getting a 1 or a 2 is:

P(1 or 2) = P(1) + P(2) = 1/6 + 1/6 = 1/3

Note that this formula only works for mutually exclusive events. If the events are not mutually exclusive, we need to use a different formula to calculate their probabilities.