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If P (A) = 6 11 , P (B) = 5 11 and P (A ∪ B) = 7 11 , Find (I) P (A ∩ B) (Ii) P (A/B) (Iii) P (B/A) - Mathematics

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प्रश्न

If P (A) = \[\frac{6}{11},\]  P (B) = \[\frac{5}{11}\]  and P (A ∪ B) = \[\frac{7}{11},\]  find

(i) P (A ∩ B)
(ii) P (A/B)
(iii) P (B/A)
योग

उत्तर

Given: 

\[P\left( A \right) = \frac{6}{11}\]

\[P\left( B \right) = \frac{5}{11} \]

\[P\left( A \cup B \right) = \frac{7}{11}\]

\[\text { (i) P\left( A \cup B \right) = P\left( A \right) + P\left( B \right) - P\left( A \cap B \right)\]

\[ \Rightarrow \frac{7}{11} = \frac{6}{11} + \frac{5}{11} - P\left( A \cap B \right)\]

\[ \Rightarrow P\left( A \cap B \right) = \frac{6}{11} + \frac{5}{11} - \frac{7}{11} = \frac{4}{11}\]

\[\text{(ii) } P\left( A/B \right) = \frac{P\left( A \cap B \right)}{P\left( B \right)}\]

\[ = \frac{\frac{4}{11}}{\frac{5}{11}}\]

\[ = \frac{4}{5}\]

\[\text {(iii) } P\left( B/A \right) = \frac{P\left( A \cap B \right)}{P\left( A \right)}\]

\[ = \frac{\frac{4}{11}}{\frac{6}{11}}\]

\[ = \frac{4}{6}\]

\[ = \frac{2}{3}\]

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Probability Examples and Solutions
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अध्याय 31: Probability - Exercise 31.3 [पृष्ठ ३४]

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आरडी शर्मा Mathematics [English] Class 12
अध्याय 31 Probability
Exercise 31.3 | Q 7 | पृष्ठ ३४

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