Question

    The average age of (x + 7) trainees is 17 years. When a

    39-year-old trainer joins, the average becomes 18 years. Find x% of 500.
    A 70 Correct Answer Incorrect Answer
    B 65 Correct Answer Incorrect Answer
    C 75 Correct Answer Incorrect Answer
    D 80 Correct Answer Incorrect Answer

    Solution

    Total age = 17(x + 7)
    According to question,
    [17(x + 7) + 39] = 18(x + 7 + 1)
    17x + 119 + 39 = 18x + 144
    18x - 17x = 158 - 144
    x = 14
    So, 14% of 500 = 70

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