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If for two events A and B, P(A) = 34, P(B) = 25 and A ∪ B = S (sample space), find the conditional probability P(A/B)

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प्रश्न

If for two events A and B, P(A) = `3/4`, P(B) = `2/5`  and A ∪ B = S (sample space), find the conditional probability P(A/B)

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उत्तर

Given P(A) = `3/4`

P(B) = `2/5`

A ∪ B = S

n(A ∪ B) = n(S)

P(A ∪ B) = `("n"("A" ∪ "B"))/("n"("S"))`

P(A ∪ B) = `("n"("S"))/("n"("S"))` = 1

P(A/B) = `("n"("A" ∩ "B"))/("P"("B"))`

= `("P"("A") + "P"("B") - "P"("A" ∪ "B"))/("P"("B"))`

= `(3/4 + 28/5 - 1)/(2/5)`

= `((15 + 8 - 20)/20)/(2/5)`

= `(23 - 20)/20 xx 5/2`

P(A/B) = `3/20 xx 5/2`

= `3/8`

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पाठ 12: Introduction to probability theory - Exercise 12.3 [पृष्ठ २५८]

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सामाचीर कलवी Mathematics - Volume 1 and 2 [English] Class 11 TN Board
पाठ 12 Introduction to probability theory
Exercise 12.3 | Q 5 | पृष्ठ २५८

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