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    Question

    The mean weight of 'w' students in a classroom is 42 kg.

    When the class teacher, weighing 61.5 kg, is added to the group, the average weight increases by 0.5 kg. Determine the number of students in the class.
    A 40 Correct Answer Incorrect Answer
    B 25 Correct Answer Incorrect Answer
    C 35 Correct Answer Incorrect Answer
    D 38 Correct Answer Incorrect Answer
    E none of these Correct Answer Incorrect Answer

    Solution

    ATQ, Total weight of students = 42w kg Total weight of students including class teacher = 42.5 × (w + 1) kg 42w + 61.5 = 42.5 × (w + 1) 42w + 61.5 = 42.5x + 42.5 0.5w = 19 w = 38 Required number of students = 38

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