The ball so drawn is found to be red in colour Find the probability that the
transferred ball is black Choose the correct answer in each of the following:
17 If A and B are two events such that P(A) ≠ 0 and P(B | A) = 1, then
(A) A ⊂ B
(B) B ⊂ A
(C) B = φ
(D) A = φ
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