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

    Question

    The average age of a class of 20 girls is 15 years. If 5

    new girls having average age of 10 years join the class, then the average age of the class becomes:
    A 15 years Correct Answer Incorrect Answer
    B 13.6 years Correct Answer Incorrect Answer
    C 16.5 years Correct Answer Incorrect Answer
    D 14 years Correct Answer Incorrect Answer

    Solution

    Total age of 20 girls = 20 × 15 = 300 years Total age of 25 girls = 300 + (5 × 10) = 300 + 50 = 350 years Therefore new average age = 350/25 = 14 years

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