a bag contains 5 red 8 green and 7 white balls - Wikitechy https://www.wikitechy.com/interview-questions/tag/a-bag-contains-5-red-8-green-and-7-white-balls/ Interview Questions Mon, 06 Sep 2021 05:50:30 +0000 en-US hourly 1 https://wordpress.org/?v=6.9.4 https://www.wikitechy.com/interview-questions/wp-content/uploads/2025/10/cropped-wikitechy-icon-32x32.png a bag contains 5 red 8 green and 7 white balls - Wikitechy https://www.wikitechy.com/interview-questions/tag/a-bag-contains-5-red-8-green-and-7-white-balls/ 32 32 A bag contains 8 red and 5 white balls. 2 balls are drawn at random. What is the probability that both are white ? https://www.wikitechy.com/interview-questions/probability/a-bag-contains-8-red-and-5-white-balls-2-balls-are-drawn-at-random-what-is-the-probability-that-both-are-white/ https://www.wikitechy.com/interview-questions/probability/a-bag-contains-8-red-and-5-white-balls-2-balls-are-drawn-at-random-what-is-the-probability-that-both-are-white/#respond Wed, 18 Aug 2021 02:08:13 +0000 https://www.wikitechy.com/interview-questions/?p=2050

A bag contains 8 red and 5 white balls. 2 balls are drawn at random. What is the probability that both are white ?

A. 5/16

B. 2/13

C. 3/26

D. 5/39

Answer : D. 5/39

Explanation:

  • n(S) = Number of methods for drawing 2 balls out of 13 = 13C2
    = (13 x 12) / 2
    = 78.
  • n(E) = No. of methods for drawing 2 balls out of 5 = 5C2
    = (5 x 4) / 2
    = 10.
  • Therefore, P(E) = n(E) / n(S)
    = 10/78
    = 5/39.
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