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If the Probability of a to Fail in an Examination is 1 5 and that of B is 3 10 . Then, the Probability that Either a Or B Fails is - Mathematics

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प्रश्न

If the probability of A to fail in an examination is \[\frac{1}{5}\]  and that of B is \[\frac{3}{10}\] . Then, the probability that either A or B fails is

 
 

विकल्प

  • 1/2

  • 11/25

  •  19/50

  •  none of these

     
MCQ
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उत्तर

19/50

Given:
P(A) = \[\frac{1}{5}\]

∴ P(A') = \[1 - \frac{1}{5} = \frac{4}{5}\]

P(B) = \[\frac{3}{10}\]

∴ P(B') = \[1 - \frac{3}{10} = \frac{7}{30}\]

Hence, required probability = P(A∩ B') + P(A'∩ B)

\[= \frac{1}{5} \times \frac{7}{10} + \frac{4}{5} \times \frac{3}{10}\]
\[ = \frac{7}{50} + \frac{12}{50}\]
\[ = \frac{19}{50}\]
 
 

 

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Concept of Probability - Probability of 'Not', 'And' and 'Or' Events
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अध्याय 33: Probability - Exercise 33.6 [पृष्ठ ७२]

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आरडी शर्मा Mathematics [English] Class 11
अध्याय 33 Probability
Exercise 33.6 | Q 21 | पृष्ठ ७२

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