SSC Quantitative Aptitude Mensuration Question Bank Mensuration-II (I)

  • question_answer
    Let A and B be two solid spheres such that the surface area of B is300% higher than the surface area of A the volume of A is found to be k% lower than the volume of B. The value of k must be

    A) 85.5

    B) 92.5

    C) 90.5

    D) 87.5

    Correct Answer: D

    Solution :

    [d] Let the radius of solid spheres be \[{{r}_{1}}\] and \[{{r}_{2}}\] respectively. According to the question, Surface area of B = 400% of surface area of A \[\Rightarrow \]   \[4\pi r_{2}^{2}=16\pi r_{1}^{2}\]\[\Rightarrow \]\[\frac{{{r}_{1}}}{{{r}_{2}}}=\sqrt{\frac{1}{4}}=\frac{1}{2}\,\text{or}\,1:2\] Given, Volume of \[B\times \frac{(100-k)}{100}\] Volume of A \[\Rightarrow \]   \[\frac{4}{3}\pi r_{2}^{3}\left( \frac{100-k}{100} \right)=\frac{4}{3}\pi r_{1}^{3}\] \[\Rightarrow \]   \[{{\left( \frac{{{r}_{1}}}{{{r}_{2}}} \right)}^{3}}=\frac{100-k}{100}\]\[\Rightarrow \]\[\frac{1}{8}=\frac{100-k}{100}\] \[\Rightarrow \]   \[k=\frac{700}{8}=87.5\]


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