Question

Events A and B are disjointed. P(A) = ; P(B) = . Find P(A or B).

Answer 1

Solutions

⇒ Disjointed

Two sets A and B are disjoint if they have no elements in common. In other words the intersection is empty, A∩B=∅A∩B=∅.

There is nothing in common between A and B.

P(A or B) = P(A) + P(B).

Answer 2

Since they are disjointed it means, nothing is common between A and B.

That is the probability of A and B occurring at the same time is zero.

Therefore :

P(A or B) = P(A) + P(B).

That is the answer.

I hope this helps.