Final answer:
To find P(A) when given P(B), P(A|B), and P(B|A), we can use the formula P(A|B) = P(A ∩ B) / P(B). Rearrange the equation to solve for P(A), and substitute the given values to find P(A) = 0.4.
Step-by-step explanation:
P(A|B) represents the conditional probability of event A given that event B has already occurred. In this case, we are given P(A|B) = 0.4 and P(B|A) = 0.5. We need to find P(A). We can use the formula:
P(A|B) = P(A ∩ B) / P(B)
Substituting the given values, we have 0.4 = P(A ∩ B) / 0.3. Rearranging the equation, we get:
P(A ∩ B) = 0.4 * 0.3 = 0.12
Since P(A ∩ B) = P(A|B) * P(B), we can write:
P(A ∩ B) = P(A) * P(B)
Therefore, 0.12 = P(A) * 0.3. Solving for P(A), we find:
P(A) = 0.12 / 0.3 = 0.4