Question

Event A occurs with probability 0.2. Event B occurs with probability 0.8. If A and B are disjoint (mutually exclusive), then

A) P(A and B) = 0.16
B) P(A or B) = 1.0
C) P(A and B) = 1.0
D) P(A Or B) = 0.16

Answer 1

What's the question? Do you want to prove these statements?

Answer 2

B.

Explanation:

If A and B are disjoint events, then P(A∩B) = 0 (because A and B haven't common parts), intersection ∩ can be also denoted with "and", so P(A and B) =0.

On the other hand, if A and B are disjoint events, then P(AUB) = P(A)+P(B). Union U can be also denoted with "or", then P(A or B) = P(A)+P(B).

P(A or B)= 0.2+0.8 = 1.

So, the answer is B.