Railways Sample Paper RRBs Assistant Loco Pilot and Technician CBT STAGE-I Sample Paper-28

  • question_answer
    The difference between compound interest and simple interest on a sum for 2 yr at 8% per annum is 7 768. The sum is

    A)  Rs. 100000

    B)  Rs. 110000

    C)  Rs. 120000      

    D)  Rs. 170000

    Correct Answer: C

    Solution :

    Let the sum be Rs. x. Then, SI = Rs.\[\left( x\times \frac{8}{100}\times 2 \right)=\]Rs. \[\frac{4x}{25}\] CI = Rs. \[\left[ x\times {{\left( 1+\frac{8}{100} \right)}^{2}}-x \right]\] = Rs. \[\left[ x\frac{27}{25}\times \frac{27}{25}-x \right]=\]Rs. \[\frac{104}{625}\] \[(CI)-(SI)=\text{Rs}.\,\,\left( \frac{104x}{625}-\frac{4x}{25} \right)=\]Rs. \[\frac{4x}{625}\] \[\therefore \]\[\frac{4x}{625}=768\Rightarrow x=\left( \frac{768\times 625}{4} \right)=120000\] \[\therefore \] Sum = Rs. 120000

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