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    Question

    The average of 11 observations is 60. If the average of

    first five observations is 58 and that of last five is 56, the sixth observation is
    A 90 Correct Answer Incorrect Answer
    B 110 Correct Answer Incorrect Answer
    C 85 Correct Answer Incorrect Answer
    D 100 Correct Answer Incorrect Answer

    Solution

    Average of 11 observations = 60

    Average of first 5 observations = 58

    Average of last 5 observations = 56


    Total of 11 observations=11×60=660


    Total of first 5 observations=5×58=290


    Total of last 5 observations=5×56=280

    Now, add the total of the first 5 and last 5: 290 + 280 = 570
    Required answer = 660 − 570 = 90 ​

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