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If P(A)=0.4P(A) = 0.4, P(B)=XP(B) = X and P(Aˉ∩Bˉ)=0.4P(\bar{A} \cap \bar{B}) = 0.4, where A and B are independent event, then the value of X is:

Solution

✅ Correct Option: 3

If AA and BB are independent, so are their complements. Hence P(Aˉ∩Bˉ)=P(Aˉ)P(Bˉ)P(\bar{A}\cap\bar{B}) = P(\bar{A})P(\bar{B}).

So 0.4=0.6(1−X)0.4 = 0.6(1-X), giving 1−X=2/31-X = 2/3 and X=1/3X = 1/3.

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