Hello Naresh,
Given, P(B) = 2/7, P(A U B') = 4/5
As A and B are independent events, P(A U B) = P(A) + P(B)
=>P(A U B') = P(A) + 1 - P(B) [As P(B') = 1 - P(B)]
=>4/5 = P(A) + 1 - 2/7 [P(B') = 1-2/7=5/7]
=>P(A) = 3/35
This is a simple question on probability. Do pay attention to the reasons in the brackets.
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