InterviewSolution
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If A and B are mutually exclusive events such that P(A) = 0.35 and P(B) = 0.45, find (i) P (A∪B) (ii) P (A∩B)(iii) \(P (A∩\bar{B})\)(iv) \(P (\bar{A}∩\bar{B})\) |
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Answer» Given A and B are two mutually exclusive events And, P(A) = 0.35 P(B) = 0.45 By definition of mutually exclusive events we know that: P(A ∪ B) = P(A) + P(B) We have to find i) P(A ∪ B) = P(A) + P(B) = 0.35 + 0.45 = 0.8 ii) P(A ∩ B) = 0 {∵ nothing is common between A and B} iii) P(A ∩ B’) = This indicates only the part which is common with A and not B ⇒ This indicates only A. P(only A) = P(A) – P(A ∩ B) As A and B are mutually exclusive So they don’t have any common parts ⇒ P(A ∩ B) = 0 ∴ P(A ∩ B’) = P(A) = 0.35 iv) P(A’ ∩ B’) = P(A ∪ B)’ {using De Morgan’s Law} ⇒ P(A’ ∩ B’) = 1 – P(A ∪ B) = 1 – 0.8 = 0.2 |
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