Answer: The probability of a sure event, also known as a certain event, is always equal to 1.

In probability theory, a sure event is an event that is certain to occur. This means that the outcome of the event is guaranteed. Therefore, the probability of a sure event occurring is 1, or 100%.

Mathematically, if P(A) represents the probability of event A, then for a sure event A, we have:

P(A) = 1

This means that the event is guaranteed to happen.

The probability of occurrence of an event is the number of trials in which the event happened divided by the total number of trials.