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    Question

    36 pens are there in a box where 12 are red pens,

    ‘p’ are blue pens and remaining are black pens. If a pen is picked, the probability of getting blue pen is 0.25. Find the ratio of the number of blue pens and black pens.
    A 5:2 Correct Answer Incorrect Answer
    B 3:5 Correct Answer Incorrect Answer
    C 6:7 Correct Answer Incorrect Answer
    D 2:1 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Probability of getting a blue  pen , => p/36 = 1/4 => p = 9 So, number of black  pens  = 36 – 12 – 9 = 15 Required ratio = 9 : 15 = 3:5

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