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

    Question

    A box contains only three colors of balls- red, green,

    and blue. What is the minimum number of balls that should be picked from the box to ensure that at least 9 red balls or at least 10 green balls or at least 11 blue balls are picked?
    A 21 Correct Answer Incorrect Answer
    B 28 Correct Answer Incorrect Answer
    C 42 Correct Answer Incorrect Answer
    D 63 Correct Answer Incorrect Answer

    Solution

    If we pick at least 8 red balls, 9 green balls and 10 blue balls from the box, the total number of balls picked from the box will be 27. If one more ball is picked from the box, irrespective of what it is, it can be said that at least 9 red balls or at least 10 green balls or at least 11 blue balls have been picked from the basket. Hence, required number of balls = 27 + 1 = 28

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