New SIDBI Grade A New Batch Starts on Nov 18

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    Question

    A bag contains 24 white and some black balls. If the probability of drawing a black ball from the bag is 1.5 times that of drawing a white ball, find the number of black balls in the bag.

    A 20 Correct Answer Incorrect Answer
    B 30 Correct Answer Incorrect Answer
    C 26 Correct Answer Incorrect Answer
    D 36 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Number of white balls = 24
    Let x be the number of black balls.
    Total number of balls in the bag = 24 + x
    Also, the probability of drawing a black ball from the bag is 1.5 times that of drawing a white ball.
    ⇒ x/(24 + x) = 1.5 [24/(24 + x)]
    ⇒ x = 1.45 × 24 = 36
    Hence, the number of black balls in the bag = 36

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