Given:
[tex]\[ P(A)=0.60, \, P(B)=0.20, \, \text{and} \, P(A \text{ and } B)=0.15. \][/tex]

What is [tex]\( P(A \text{ or } B) \)[/tex]?

A. 0.80
B. 0.12
C. 0.65
D. 0.40



Answer :

To determine the probability of either event [tex]\(A\)[/tex] or event [tex]\(B\)[/tex] occurring, we use the formula for the probability of the union of two events. This formula is given by:

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

Where:
- [tex]\(P(A)\)[/tex] is the probability of event [tex]\(A\)[/tex] occurring.
- [tex]\(P(B)\)[/tex] is the probability of event [tex]\(B\)[/tex] occurring.
- [tex]\(P(A \text{ and } B)\)[/tex] is the probability that both events [tex]\(A\)[/tex] and [tex]\(B\)[/tex] occur simultaneously.

Given:
- [tex]\(P(A) = 0.60\)[/tex]
- [tex]\(P(B) = 0.20\)[/tex]
- [tex]\(P(A \text{ and } B) = 0.15\)[/tex]

Substitute these values into the formula:

[tex]\[ P(A \text{ or } B) = 0.60 + 0.20 - 0.15 \][/tex]

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

[tex]\[ 0.60 + 0.20 = 0.80 \][/tex]

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

[tex]\[ 0.80 - 0.15 = 0.65 \][/tex]

Therefore, the probability of either event [tex]\(A\)[/tex] or event [tex]\(B\)[/tex] occurring is:

[tex]\[ P(A \text{ or } B) = 0.65 \][/tex]

The correct answer is:
C. 0.65