हिंदी

Given that the events A and B are such that andP(A)=12,PA∪B=35andP(B)=p. Find p if they are i. mutually exclusive ii. independent.

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प्रश्न

Given that the events A and B are such that `P(A) = 1/2, PA∪B=3/5 and P (B) = p`. Find p if they are

  1. mutually exclusive
  2. independent.
योग
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उत्तर

i. Since the events are mutually exclusive.

∴ P(A ∩ B) = 0

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

∴ `3/5 = 1/2 + p - 0`

⇒ p = `3/5 - 1/2 = (6 - 5)/10 = 1/10`

ii. The events are independent.

∴ P(A ∩ B) = P(A) . P(B)

= `1/2 . p`

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

and  `3/5 = 1/2 + p - 1/2 p`

or `1/2 p = 3/5 - 1/2 = (6 - 5)/10 = 1/10`

⇒ p = `2/10 = 1/5`

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अध्याय 13: Probability - Exercise 13.2 [पृष्ठ ५४७]

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एनसीईआरटी Mathematics Part 1 and 2 [English] Class 12
अध्याय 13 Probability
Exercise 13.2 | Q 7 | पृष्ठ ५४७

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