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Discussion :: Probability

  1. A bag contains 4 white, 5 red and 6 blue balls. Three balls are drawn at random from the bag. The probability that all of them are red, is:

  2. A.

    122

    B.

    322

    C.

    221

    D.

    277

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    Answer : Option C

    Explanation :

    Let S be the sample space.

     

    Then, n(S) = number of ways of drawing 3 balls out of 15
      15C3

     

                  = (151413)(321)

     

                  = 455

     

      Let E = event of getting all the 3 red balls.

     

       n(E) = 5C3 = 5C2 =(51)(21)=10

     

      P(E) =n(E)n(S)=10455=221

     


Psr said : (Jan 22, 2022)

10/455 is 2/91.