2. Sample Papers
  3. Railways

Railways Sample Paper RRBs Assistant Loco Pilot and Technician CBT STAGE-I Sample Paper-34

  • question_answer
    If \[x=a(b-c),y=b(c-a)\]and\[z=c(a-b)\]then \[{{\left( \frac{x}{a} \right)}^{3}}+{{\left( \frac{y}{b} \right)}^{3}}+{{\left( \frac{z}{c} \right)}^{3}}\]

    A)  \[\frac{xyz}{3abc}\]     

    B)  \[3\,xyzabc\]

    C)  \[\frac{3xyz}{abc}\]     

    D)  \[\frac{xyz}{abc}\]

    Correct Answer: C

    Solution :

    \[\frac{x}{a}=b-c;\,\,\frac{y}{b}=c-a;\,\,\frac{z}{c}=a-b\] Again,\[b-c+c-a+a-b=0\] \[\therefore \]      \[{{\left( \frac{x}{a} \right)}^{3}}+{{\left( \frac{y}{b} \right)}^{3}}+{{\left( \frac{z}{c} \right)}^{3}}\] \[={{(b-c)}^{3}}+{{(c-a)}^{3}}+{{(a-b)}^{3}}\] \[=3(b-c)(c-a)(a-b)=\frac{3xyz}{abc}\]


You need to login to perform this action.
You will be redirected in 3 sec spinner