If the probability of event A, P(A)=1.00 then what is A’

The complement of event A, denoted as A', is the probability of the event not occurring. If the probability of event A, P(A), is 1.00 (or 100%), it means that event A is certain to happen. Therefore, the probability of A' (the event not occurring) would be 0.00 or 0% since there is no possibility of it happening.