What does the union of two events A and B contain?

The union of two events, denoted as A ∪ B, encompasses all the sample points that belong to either event A, event B, or both events simultaneously. This means that if you were to create a set containing all the elements from both A and B, you would not omit any element from either event.

In practical terms, if you think of A and B as groups of outcomes from an experiment, the union captures everything you can get from either group, ensuring that no possible outcome is left out. This is a fundamental concept in set theory and probability, where the union represents a comprehensive collection of scenarios defined by the events in question.