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JEE Main & Advanced JEE Main Online Paper (Held on 9 April 2013)

  • question_answer
                    The mean of a data set consisting of 20 observations is 40. If one observation 53 was wrongly recorded as 33, then the correct mean will be:               JEE Main Online Paper (Held On 09 April 2013)    

    A)                 41                

    B)                 49                

    C)                 40.5                

    D)                 42.5

    Correct Answer: A

    Solution :

                    Given; \[\frac{\sum{{{x}_{20}}}}{20}=40\Rightarrow \sum{{{x}_{20}}}=20\times 40=800\] \[\therefore \]  \[\sum{{{x}_{20}}}=800-33+53=820\] \[\Rightarrow \]               \[\frac{\sum{{{x}_{20}}}}{20}=\frac{820}{20}\] \[\therefore \] New mean \[=41\]                


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