Question

    The average of a set of 60 numbers was initially

    calculated as 40. However, it was later discovered that two numbers were incorrectly recorded as 68 and 32, instead of the correct values 86 and 23. Determine the accurate mean after correcting these errors.
    A 40.15 Correct Answer Incorrect Answer
    B 42.35 Correct Answer Incorrect Answer
    C 37.75 Correct Answer Incorrect Answer
    D None of the above Correct Answer Incorrect Answer

    Solution

    Initially, mean of 60 numbers = 40

    So, sum of 60 numbers = 60 X 40 = 2,400
    ATQ, Correct sum = 2,400 - (68 + 32) + (86 + 23) = 2,409

    Correct mean = (2,409/60) = 40.15

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