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    Question

    The average height of each person in group 'I' having 36

    people is 18 cm less than the average height of each person in group 'J' having 30 people. If the sum of the heights of all people in group 'I' is the same as that in group 'J', then what is the average height of a person in group 'J'?
    A 120 cm Correct Answer Incorrect Answer
    B 108 cm Correct Answer Incorrect Answer
    C 104 cm Correct Answer Incorrect Answer
    D 128 cm Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    ATQ, Let the average height of a person in group 'J' = 'b' cm. Then, the average height of a person in group 'I' = (b - 18) cm. Total height of all people in group 'J' = 30 × b = '30b' cm. Total height of all people in group 'I' = 36 × (b - 18) = 36b - 648 cm. So, 36b - 648 = 30b. Or, 6b = 648. So, b = 648 / 6 = 108. Required average height = 108 cm.

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