8th Class Mathematics Sample Paper Mathematics Sample Paper - 4

  • question_answer
    The denominator of a rational number is greater then its numerator by 8. If the numerator is increased by 17 and the denominator is decreased by 1, the number obtained is \[\frac{3}{2}\] . Find the rational number.

    Answer:

    Let the numerator of rational number be x
    and                  denominator = x + 8
    Therefore rational number \[=\frac{x}{x+8}\]                                                                                                                                         
    According to question,
    \[\frac{x+17}{(x+8)-1}=\frac{3}{2}\]
    or,      \[\frac{x+17}{x+7}=\frac{3}{2}\]                                                       
    or,            \[2(x+17)=3(x+7)\]               
    or,                    \[2x+34=3x+21\]   
    or      \[2x-3x=21-34\]
    [Transposing 3x to LHS and 34 to RHS]
    or,                           \[-x\text{ }=-13~~\]
    or,                             x = 13
    Hence, the required rational number
    \[=\frac{13}{13+8}=\frac{13}{21}\]
         


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