What is the addition rule of probability for two mutually exclusive events A and B?

The addition rule of probability states that for two mutually exclusive events, the probability that either event A occurs or event B occurs is equal to the sum of their individual probabilities. This means that when events are mutually exclusive, they cannot occur at the same time, and therefore, the occurrence of one does not affect the occurrence of the other.

In this case, if you want to find the probability of either event A happening or event B happening, you can simply add the probabilities of A and B together. Hence, the formula P(A or B) = P(A) + P(B) accurately represents this concept, confirming that when dealing with mutually exclusive events, you can directly combine their probabilities without any adjustments or considerations for overlap.

This principle is fundamental in probability theory as it lays the groundwork for understanding how to calculate probabilities for combined events, especially in scenarios where events are distinctly separate from one another.