Question 3

Mathematics Probability Medium

Let \(P(E)\) denote the probability of event \(E\). Given \(P(A)=1, P(B)=\frac{1}{2}\), the value of \(P(A \mid B)\) and \(P(B \mid A)\) respectively are

(A) \(\frac{1}{4}, \frac{1}{2}\)
(B) \(\frac{1}{2}, \frac{1}{4}\)
(C) \(\frac{1}{2}, 1\)
(D) \(1, \frac{1}{2}\)
View Dynamic Solution & Explanation
Correct Solution: Option D

Step-by-step Solution:

\(\mathrm{P}(A \cup B)=P(\mathrm{a})+P(B)-P(A \cap B)\) \[\] \(1=1+\frac{1}{2}-P(A \cap B)\) \[\] \(P(A \cap B)=\frac{1}{2}\) \[\] \(P(A / B)=\frac{P(A \cap B)}{P(B)}=\frac{\frac{1}{2}}{\frac{1}{2}}=1\) \[\] \(P(B / A)=\frac{P(B \cap A)}{P(A)}=\frac{1 / 2}{1}=\frac{1}{2}\) \[\] Choice (D)\[\]