Question

    Average weight of each student, in a class of 70

    students, is 86kg. If the ratio of number of boys and girls in the class is 4:3, respectively and average weight of each boy in the class is 92kg, then find the average weight of each girl in the class.
    A 78 Correct Answer Incorrect Answer
    B 44 Correct Answer Incorrect Answer
    C 65 Correct Answer Incorrect Answer
    D 58 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Number of boys in the class = 70 × (4/7) = 40 Number of girls in the class = 70 × (3/7) = 30 Let the weight of each girl in the class be ‘x’ kg. {(40 × 92) + (30 × x)} ÷ {30 + 40} = 86 Or, 3680 + 30x = 6020 Or, 30x = 2340 So, x = 78 Therefore, average weight of each girl in the class = 78kg

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