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    Question

    The average age of a group of students in a school is 14

    years. If 20% of them have an average age of 12 years and 40% have an average age of 16 years, then the rest students have an average age of
    A 13.4 years Correct Answer Incorrect Answer
    B 13 years Correct Answer Incorrect Answer
    C 12 years Correct Answer Incorrect Answer
    D 12.5 years Correct Answer Incorrect Answer

    Solution

    Let the total number of students be 100 So sum of the age of total students = 100 x 14 = 1400 20% of the students have average of 12 = 20% of 100 x 12 = 240 40% of the students have average of 16 = 40% of 100 x 16 = 640 Average of rest of the students = 100% - 60% = 40% Required average = (1400 – 240 – 640)/40 = 13 years Alternate method:

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