[tex]$A$[/tex] and [tex]$B$[/tex] are mutually exclusive events. [tex]$P(A) = 0.50$[/tex] and [tex]$P(B) = 0.30$[/tex]. What is [tex]$P(A \text{ or } B)$[/tex]?

A. 0.20
B. 0.65
C. 0.90
D. 0.80



Answer :

To determine the probability of the event [tex]\( A \)[/tex] or [tex]\( B \)[/tex] occurring, when [tex]\( A \)[/tex] and [tex]\( B \)[/tex] are mutually exclusive events, we use the addition rule for mutually exclusive events. The rule states:

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

Since [tex]\( A \)[/tex] and [tex]\( B \)[/tex] are mutually exclusive, they cannot happen at the same time. Therefore, the probability of [tex]\( A \text{ or } B \)[/tex] is simply the sum of their individual probabilities.

Given:
[tex]\[ P(A) = 0.50 \][/tex]
[tex]\[ P(B) = 0.30 \][/tex]

Now, applying the rule:
[tex]\[ P(A \text{ or } B) = P(A) + P(B) \][/tex]
[tex]\[ P(A \text{ or } B) = 0.50 + 0.30 \][/tex]
[tex]\[ P(A \text{ or } B) = 0.80 \][/tex]

Hence, the probability of either event [tex]\( A \)[/tex] or event [tex]\( B \)[/tex] occurring is [tex]\( 0.80 \)[/tex].

The correct answer is:
D. 0.80
Correct Answer: (B) 0.65

Explanation:

The rule for an either/or probability is
P (A or B) = P(A) + P(B) - P(A∩B)

=0.50+0.30 - P(A) × P(B)

=0.80- (0.5 × 0.3)

=0.80 - 0.15

=0.65