Events that cannot occur at the same time are mutually exclusive. Mutually exclusive events have no outcomes in common. For example, because it is not possible to toss a coin and obtain heads and tails at the same time, these two events are mutually exclusive.
Rules for Probability
If A and B are mutually exclusive events, the probability that A and B will occur is P(AandB)=0.
If A and B are not mutually exclusive events, the probability that A and B will occur is P(AandB)≠0.
We roll a pair of dice at the same time.
Let A be getting a sum of 7 and B be getting 6 on the face of one die.
If we roll one and six on a pair of dice, we get a sum of 7 and 6 on the face of one die. Therefore, A and B are not mutually exclusive events.
