8th Class Mathematics Direct and Inverse Proportions Question Bank Direct and Inverse Proportions

  • question_answer
    If \[\frac{15}{5}:\frac{1}{x}=\frac{1}{x}:\frac{1}{125}\] then the value of x is_____.

    A)  1.25   

    B)  1.5     

    C)  25                  

    D)         2.25   

    Correct Answer: C

    Solution :

    We have, \[\frac{1}{5}:\frac{1}{x}=\frac{1}{x}:\frac{1}{125}\] \[\Rightarrow \frac{1}{x}\times \frac{1}{x}=\frac{1}{5}\times \frac{1}{125}\Rightarrow \frac{1}{{{x}^{2}}}=\frac{1}{625}\] \[\Rightarrow {{x}^{2}}=625\Rightarrow x=25\].


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