New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    40 pens are there in a box where 22 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 5:4 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/40 = 1/4 => p = 10 So, number of black  pens  = 40 – 10 – 22 = 8 Required ratio = 10 : 8 = 5:4

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