New Enroll for RBI, PFRDA & NABARD Intro Class! April 18 at 9:15 PM

    Question

    A bag contains (K - 2) red balls, 8 black balls, and 14

    blue balls. If two balls are drawn randomly, the probability that both are black is 2/27. Calculate 180% of the difference between the number of red and blue balls.
    A 14 Correct Answer Incorrect Answer
    B 15.6 Correct Answer Incorrect Answer
    C 12.4 Correct Answer Incorrect Answer
    D 14.6 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Let total number of balls in the bag = a So according to question, 8C2 / aC2 = 2/27 (8 x 7) / a x (a – 1) = 2/27 So, a x (a – 1) = 28 x 27 So total number of balls in the bag = 28 balls So number of red balls = 28 – (14 + 8) = 6 Required value = 180% x (14 – 6) = 14.4 Hence answer is option E

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