Finite Math Examples

$P (A) = 0.78$ , $P (B) = 0.09$

Step 1

When $A$ and $B$ are mutually exclusive events, the probability of $A$ or $B$ occurring is $P (A \cup B) = P (B \cup A) = P (A) + P (B)$ , which is called the addition rule for mutually exclusive events $A$ and $B$ .

$P (A \cup B) = P (B \cup A) = P (A) + P (B)$

Step 2

Fill in the known values.

$P (A \cup B) = P (B \cup A) = 0.78 + 0.09$

Step 3

Add $0.78$ and $0.09$ .

$P (A \cup B) = P (B \cup A) = 0.87$