Banking Quantitative Aptitude Sample Paper Quantitative Aptitude Sample Paper-2

  • question_answer
    Average of n number 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) Pre 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] New average \[=\,\,\frac{na+2+4+8+16+....+{{2}^{n}}}{n}\]
    \[=\,\,\,\frac{na+2\left( \frac{{{2}^{n}}-1}{2-1} \right)}{n}=a+2\cdot \frac{{{2}^{n}}-1}{n}\]


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