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  4. Quantitative Aptitude
  5. Number System and its Operations

Railways Quantitative Aptitude Number System and its Operations Sample Paper Number System Sample Test Paper-1

  • question_answer
    Find the whole number which when increased by 20 is equal to 69 times the reciprocal of the number:

    A)  7

    B)                     5        

    C)  3                    

    D)  2.5

    Correct Answer: C

    Solution :

    [c] Let the whole number be x According to question \[x+20=\frac{69}{x}\] \[\Rightarrow \]   \[{{x}^{2}}+20x=69\] \[\Rightarrow \]   \[{{x}^{2}}+20x-69=0\] \[\Rightarrow \]   \[{{x}^{2}}+23x-3x-69=0\] \[\Rightarrow \]   \[x(x+23)-3(x+23)=0\] \[\Rightarrow \]   \[(x+23)(x-3)=0\] \[\therefore \] x=3 or \[-23,\] Hence, 3 is only whole number.


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