Suppose [tex]$A$[/tex] and [tex]$B$[/tex] are dependent events. If [tex]$P(A)=0.4$[/tex] and [tex]$P(B \mid A)=0.8$[/tex], what is [tex][tex]$P(A \cap B)$[/tex][/tex]?

A. 0.4
B. 0.8
C. 0.32
D. 0.2



Answer :

To solve for [tex]\( P(A \cap B) \)[/tex], we can use the definition of conditional probability. The formula for conditional probability is given by:

[tex]\[ P(B \mid A) = \frac{P(A \cap B)}{P(A)} \][/tex]

Since we need to find [tex]\( P(A \cap B) \)[/tex], we can rearrange this formula to solve for [tex]\( P(A \cap B) \)[/tex]:

[tex]\[ P(A \cap B) = P(A) \times P(B \mid A) \][/tex]

Given:
[tex]\[ P(A) = 0.4 \][/tex]
[tex]\[ P(B \mid A) = 0.8 \][/tex]

Substitute these values into the formula:

[tex]\[ P(A \cap B) = 0.4 \times 0.8 \][/tex]

Multiplying these numbers together:

[tex]\[ P(A \cap B) = 0.32 \][/tex]

Thus, the probability of both events [tex]\( A \)[/tex] and [tex]\( B \)[/tex] occurring, [tex]\( P(A \cap B) \)[/tex], is [tex]\( 0.32 \)[/tex].

Therefore, the correct answer is:
C. 0.32