Recall in Section 3.5 A and B are mutually exclusive events if they cannot occur at the same time. If A occurs B cannot occur. This means that A and B do not share any outcomes and that: Mutually Exclusive: P(A and B) = 0. The complement of an event A is denoted by A' (read "A prime"). A' consists of all outcomes that are NOT in A. A few formulas involving the complement of A and A itself are: P(A) + P(A') = 1 P(A') = 1-P(A) P(A) = 1-P(A') 4. Write out the complement of the following situations: a. Joe asks 12 women out on dates and none of them accept. b. Emily is teaching a statistics lesson and at least one of student has a