Railways Sample Paper RRB (Assistant Loco Pilot) Sample Test Paper-20

  • question_answer
    The sum of a rational number and its reciprocal is \[\frac{13}{6},\] find the number.

    A)  \[\frac{2}{3}\]or \[\frac{3}{2}\]                   

    B)  \[\frac{3}{4}\]or \[\frac{4}{3}\]                   

    C)  \[\frac{2}{5}\]or \[\frac{5}{2}\]            

    D)        None of these

    Correct Answer: A

    Solution :

    Let the number be x. Then, \[x+\frac{1}{x}=\frac{13}{6}\Rightarrow \frac{{{x}^{2}}+1}{x}=\frac{13}{6}\Rightarrow 6{{x}^{2}}-13x+6=0\]\[\Rightarrow \]\[6{{x}^{2}}-9x-4x+6=0\]\[\Rightarrow \]\[(3x-2)\,(2x-3)=0\] \[\Rightarrow \] \[x=\frac{2}{3}\]   or  \[x=\frac{3}{2}\]. x 6     x    6 Hence, the required number is \[\frac{2}{3}\] or \[\frac{3}{2}\].


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