JEE Main & Advanced Sample Paper JEE Main - Mock Test - 25

  • question_answer
    The mean and median of 100 items are 50 and 52 respectively The value of largest item is 100. It was later found that it is 110 and not 100. The true mean and median are

    A) 50.10, 51.5       

    B) 50.10, 52

    C) 50, 51.5        

    D) none of these

    Correct Answer: B

    Solution :

    [b]: Here n = 100, mean = 50 and median = 52 \[\therefore \]\[\overline{x}=\frac{1}{n}\sum\limits_{i=1}^{100}{{{x}_{i}}}=50\Rightarrow \sum\limits_{i=1}^{100}{{{x}_{i}}}=5000\] Now corrected \[\sum\limits_{i=1}^{100}{{{x}_{i}}}=5000-100+110=5010\] \[\therefore \]Corrected mean \[=\frac{1}{100}\sum\limits_{i=1}^{100}{{{x}_{i}}}=\frac{5010}{100}=51.10\] As median is positional average therefore it will remain same.


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