Final answer:
The probability that either event A or event B occurs, given that they are mutually exclusive, is calculated by adding the individual probabilities of A and B, which equals 0.8 or 80%.
Step-by-step explanation:
The question is concerned with calculating the probability of either event A or B occurring when A and B are mutually exclusive events. Given the probabilities P(A) = 0.3 and P(B) = 0.5, and knowing that mutually exclusive events cannot occur together (therefore P(A AND B) = 0), the probability of either A or B occurring is found by simply adding their individual probabilities together.
So, the probability that either A or B occurs, denoted as P(A OR B), is calculated as:
P(A OR B) = P(A) + P(B) - P(A AND B) = 0.3 + 0.5 - 0 = 0.8.
The probability that either A or B occurs is 0.8 or 80%.