Railways RRB (Assistant Loco Pilot & Technician) Solved Paper-2 (2014)

  • question_answer
    If x and y are positive with \[x-y=2\]and \[xy=24,\]then \[\frac{1}{x}+\frac{1}{y}\]is equal to

    A)  \[\frac{5}{12}\]                     

    B)  \[\frac{1}{12}\]     

    C)  \[\frac{1}{6}\]                       

    D)  \[\frac{25}{6}\]

    Correct Answer: A

    Solution :

    \[\because \]  \[x-y=2\] and \[xy=24\] \[\therefore \]   \[{{(x+y)}^{2}}={{(x-y)}^{2}}+4xy\]             \[={{(2)}^{2}}+4(24)=4+96=100\] \[\therefore \]    \[x+y=10\] \[\frac{1}{x}+\frac{1}{y}=\frac{y+x}{xy}=\frac{10}{24}=\frac{5}{12}\]


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