SSC Sample Paper SSC CGL - Sample Paper-12

  • question_answer
    The arithmetic mean of the scores of a group of students in a test was 52. The brightest 20% of them secured a mean score of 80 and the dullest 25% a mean score of 31. The mean score of remaining 55% is

    A) 45%                             

    B) 50%

    C) 51.4% approx.

    D) 54.6% approx.

    Correct Answer: C

    Solution :

    Let mean score of remaining 55% = x \[52=\frac{20\times 580+25\times 31+55\times x}{100}\] \[\Rightarrow \]   \[5200=1600+775+55x\] \[\Rightarrow \]   \[55=5200+1600-775\]                  = 2825 \[\therefore \]      \[x=\frac{2825}{55}=51.36=51.4\,\,(approx.)\]  


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