Verified answer

The first two problems use P(A∪B) = P(A) + P(B) - P(A∩B) (a formula you should learn).

For the first one, the events are disjoint, so P(A∩B) = 0; thus, P(A∪B) = P(A) + P(B).

For the second one, all of the values you need for the right side are provided.

Third problem: there is no overlapping, so the probability is 100% - (30% + 25%) = 45%

Fourth problem: the events are not disjoint, because 6 is both even and a multiple of 3.