SSC Quantitative Aptitude Average Question Bank Average (I)

  • question_answer
    Average of n numbers is a. The first number is increased by 2, second one is increased by 4, the third one is increased by 8 and so on. The average of the new numbers is [SSC CGL Tier II, 2015]

    A) \[a+\frac{{{2}^{n+1}}}{n}\]

    B) \[a+2\frac{{{2}^{n}}-1}{n}\]

    C) \[a+\frac{{{2}^{n}}-1}{n}\]

    D) \[a+\frac{{{2}^{n\,+\,1}}-1}{n}\]

    Correct Answer: B

    Solution :

    [b] Total sum of n number \[=na\] According to the question, New average of numbers \[=\frac{na+(2+4+8+16+...)}{n}\] \[=a+\frac{2\,\,({{2}^{n}}-1)}{\frac{2-1}{n}}\] \[=a+\frac{2\,\,({{2}^{n}}-1)}{n}\]


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