Q17 of 105 Page 538

If A and B are events such that P(A|B) = P(B|A), then

Given: P(A|B) = P(B|A) ……….(i)


Now, we know that


By definition of conditional probability,


……….(ii)


……….(iii)


Using (i), we have


P(A|B) = P(B|A)



⇒ P(A) = P(B)

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