If p(a)=2/3, p(b)= 4/5 and p(a u b) = 3/5, what is p(a u b)? a.) 14/15 b.) 13/15 c.) 8/15 d.) 11/15

From basic probability we know that if A and B are any two events in the sample space, S, then:

......(Equation 1)

In the question we have been given all the data that is required. Thus, we have: P(A)=2/3, P(B)= 4/5 and P(A U B) = 3/5.

Substituting these values in (Equation 1) we get:

This matches Option B. Therefore, Option B is the correct answer.