How do you find the probability of A or B occurring?

To find the probability of either event A or event B occurring, it's essential to consider the possibility that both events can happen at the same time. This situation arises in cases where the events are not mutually exclusive, meaning they can overlap.

The correct approach involves adding the probabilities of A and B together and then subtracting the probability of their intersection (the probability that both A and B occur simultaneously). This subtraction accounts for the fact that when we simply add the probabilities of A and B, we inadvertently double-count the scenarios where both A and B happen together.

For example, if the probability of A occurring is 0.3, the probability of B occurring is 0.4, and the probability of both A and B occurring together is 0.1, simply adding the probabilities would result in 0.3 + 0.4 = 0.7. However, this includes the 0.1 where both events overlap, so we must subtract that intersection:

Probability of A or B = P(A) + P(B) - P(A and B) = 0.3 + 0.4 - 0.1 = 0.6.

This formula ensures an accurate calculation of the total probability for either