New 👉 Ask your RBI Grade B 2025 Preparation Queries Here!!

    Question

    A bag contains red, green, and blue balls, with a total

    of 16 balls. The probability of drawing two blue balls in one draw is 3/8. How many blue balls are in the bag?
    A 8 Correct Answer Incorrect Answer
    B 10 Correct Answer Incorrect Answer
    C 14 Correct Answer Incorrect Answer
    D 16 Correct Answer Incorrect Answer

    Solution

    Let number of blue balls in the bag be ‘x’.According to question;xC2/16C2 = 3/8Or, x(x – 1) = 90Or, x2 – x – 90 = 0Or, x2 – 10x + 9x – 90 = 0Or, x(x – 10) + 9(x – 10) = 0Or, (x – 10)(x + 9) = 0Or, x = 10 or x = -9 (not possible)So, number of blue balls in the bag = 10

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