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If A and B are two events such that P(B) = 35, P(A|B) = 12 and P(A ∪ B) = 45, then P(A) equals ______. - Mathematics

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प्रश्न

If A and B are two events such that P(B) = `3/5`, P(A|B) = `1/2` and P(A ∪ B) = `4/5`, then P(A) equals ______.

विकल्प

  • `3/10`

  • `1/5`

  • `1/2`

  • `3/5`

MCQ
रिक्त स्थान भरें

उत्तर

If A and B are two events such that P(B) = `3/5`, P(A|B) = `1/2` and P(A ∪ B) = `4/5`, then P(A) equals `1/2`.

Explanation:

Given that: P(B) = `3/5`, P(A|B) = `1/2` and P(A ∪ B) = `4/5`

We know that P(A|B) = `("P"("A" ∩ "B"))/("P"("B"))`

⇒ `1/2 = ("P"("A" ∩ "B"))/(3/5)`

∴ P(A ∩ B) = `3/10`

Now  P(A ∪ B) = P(A) + P(B) – P(A ∩ B)

`4/5 = "P"("A") + 3/5 - 3/10`

⇒ P(A) = `4/5 - 3/5 + 3/10`

= `1/5 + 3/10`

= `5/10`

= `1/2`

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अध्याय 13: Probability - Exercise [पृष्ठ २८०]

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एनसीईआरटी एक्झांप्लर Mathematics [English] Class 12
अध्याय 13 Probability
Exercise | Q 64 | पृष्ठ २८०

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