[tex]$P(A)=0.60$[/tex], [tex]$P(B)=0.30$[/tex], and [tex]$P(A$[/tex] and [tex]$B)=0.15$[/tex]. What is [tex]$P(A$[/tex] or [tex]$B)$[/tex]?

A. 0.75
B. 0.18
C. 0.15
D. 0.90



Answer :

To determine the probability of [tex]\( P(A \text{ or } B) \)[/tex], we can use the formula for the probability of the union of two events [tex]\( A \)[/tex] and [tex]\( B \)[/tex]:

[tex]\[ P(A \text{ or } B) = P(A) + P(B) - P(A \text{ and } B) \][/tex]

This formula accounts for the fact that the events [tex]\( A \)[/tex] and [tex]\( B \)[/tex] may overlap, and thus without subtracting [tex]\( P(A \text{ and } B) \)[/tex], we would be counting the overlap twice.

Given the probabilities:
- [tex]\( P(A) = 0.60 \)[/tex]
- [tex]\( P(B) = 0.30 \)[/tex]
- [tex]\( P(A \text{ and } B) = 0.15 \)[/tex]

We substitute these values into the formula:

[tex]\[ P(A \text{ or } B) = 0.60 + 0.30 - 0.15 \][/tex]

First, add [tex]\( P(A) \)[/tex] and [tex]\( P(B) \)[/tex]:

[tex]\[ 0.60 + 0.30 = 0.90 \][/tex]

Next, subtract [tex]\( P(A \text{ and } B) \)[/tex]:

[tex]\[ 0.90 - 0.15 = 0.75 \][/tex]

Thus, the probability [tex]\( P(A \text{ or } B) \)[/tex] is:

[tex]\[ P(A \text{ or } B) = 0.75 \][/tex]

Therefore, the correct answer is:
[tex]\[ \boxed{0.75} \][/tex]

This confirms that the probability of either event [tex]\( A \)[/tex] or event [tex]\( B \)[/tex] occurring is 0.75.