Question

    The average weight of a group of 5 men increases by 2 kg

    when a new person weighing 78 kg joins the group. What was the average weight of the group before the new person joined?
    A 84 kg Correct Answer Incorrect Answer
    B 78 kg Correct Answer Incorrect Answer
    C 70 kg Correct Answer Incorrect Answer
    D 66 kg Correct Answer Incorrect Answer
    E 60 kg Correct Answer Incorrect Answer

    Solution

    Let the average weight of the original 5 men be x kg. Total weight of the original 5 men = 5x After adding the new person, the total weight = 5x + 78 New average weight = x + 2 So, 5x + 78 = 6 × (x + 2) 5x + 78 = 6x + 12 78 - 12 = x x = 66

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