Probability of the Union and Intersection of Independent Events

Suppose that [tex]$A$[/tex] and [tex]$B$[/tex] are independent events such that [tex]$P(A) = 0.10$[/tex] and [tex]$P(B) = 0.50$[/tex]. Find [tex]$P(A \cap B)$[/tex] and [tex]$P(A \cup B)$[/tex]. (If necessary, consult a list of formulas.)

(a) [tex]$P(A \cap B) =$[/tex] [tex]$\square$[/tex]

(b) [tex]$P(A \cup B) =$[/tex] [tex]$\square$[/tex]



Answer :

Certainly! Let's solve the given problem step-by-step:

### Given:
- [tex]\( P(A) = 0.10 \)[/tex]
- [tex]\( P(\neg B) = 0.50 \)[/tex]

#### Step 1: Find [tex]\( P(B) \)[/tex]

Since [tex]\( \neg B \)[/tex] (not [tex]\( B \)[/tex]) is the complement of [tex]\( B \)[/tex], we can find [tex]\( P(B) \)[/tex] as follows:

[tex]\[ P(B) = 1 - P(\neg B) \][/tex]

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

[tex]\[ P(B) = 1 - 0.50 = 0.50 \][/tex]

#### Step 2: Find [tex]\( P(A \cap B) \)[/tex]

For independent events [tex]\( A \)[/tex] and [tex]\( B \)[/tex], the probability of their intersection [tex]\( P(A \cap B) \)[/tex] is given by the product of their individual probabilities:

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

Given [tex]\( P(A) = 0.10 \)[/tex] and [tex]\( P(B) = 0.50 \)[/tex]:

[tex]\[ P(A \cap B) = 0.10 \times 0.50 = 0.05 \][/tex]

So, [tex]\( P(A \cap B) = 0.05 \)[/tex].

#### Step 3: Find [tex]\( P(A \cup B) \)[/tex]

For independent events [tex]\( A \)[/tex] and [tex]\( B \)[/tex], the probability of their union [tex]\( P(A \cup B) \)[/tex] is given by:

[tex]\[ P(A \cup B) = P(A) + P(B) - P(A \cap B) \][/tex]

Given [tex]\( P(A) = 0.10 \)[/tex], [tex]\( P(B) = 0.50 \)[/tex], and [tex]\( P(A \cap B) = 0.05 \)[/tex]:

[tex]\[ P(A \cup B) = 0.10 + 0.50 - 0.05 = 0.55 \][/tex]

So, [tex]\( P(A \cup B) = 0.55 \)[/tex].

### Final Answers:
(a) [tex]\( P(A \cap B) = 0.05 \)[/tex]

(b) [tex]\( P(A \cup B) = 0.55 \)[/tex]