Question: if a and b are mutually exclusive then they are also collectively exhaustive?
Answer: "Mutually exclusive" means of any two possible outcomes A and B, the logical expression A and B cannot occur. Put another way, two propositions are mutually exclusive if the following are true: "If A, then not B" and "If B, then not A." "Collectively exhaustive" means of any set of outcomes A, B, C, D, …