Question

Let $A$ and $B$ are two events and $P \left( A '\right)=0.3, P ( B )=0.4, P \left( A \cap B '\right)=0.5$, then $P ( A \cup B)$ is.

• A. 0.5
• B. 0.9
• C. 1
• D. 0.1

Answer 1

Answer: (B)

0.9

Answer 2

Given :- $P \left( A '\right)=0.3, P ( B )=0.4, P \left( A \cap B'\right)=0.5$
$P ( A \cup B )= P ( B )+ P \left( A \cap B '\right)$
$= P ( A \cup B )=0.4+0.5$
$=0.9$