Definition: In this task you will be given a passage and a yes/no question based on the passage. You should answer the question using the information from the passage.
Input: passage: One example of an event that is both collectively exhaustive and mutually exclusive is tossing a coin. The outcome must be either heads or tails, or p (heads or tails) = 1, so the outcomes are collectively exhaustive. When heads occurs, tails can't occur, or p (heads and tails) = 0, so the outcomes are also mutually exclusive.
 question: if events a and b are mutually exclusive are they also collectively exhaustive?

Yes