SSC Sample Paper SSC CGL - Sample Paper-9

  • question_answer
    The surface areas of two spheres are in the ratio 4: 9. Their volumes will be in the ratio

    A)  2 : 3                            

    B)  4: 9

    C)  8: 27               

    D)  64: 729

    Correct Answer: D

    Solution :

    Let the radii of the first and second spheres be \[{{r}_{1}}\] and \[{{r}_{2}}\] units respectively. According to the question,             \[\frac{4\pi r_{1}^{2}}{4\pi r_{2}^{2}}=\frac{4}{9}\] \[\Rightarrow \]   \[\frac{r_{1}^{2}}{r_{2}^{2}}=\frac{4}{9}\] \[\Rightarrow \] \[\frac{{{r}_{1}}}{{{r}_{2}}}=\frac{2}{3}\] \[\therefore \] \[\frac{{{V}_{1}}}{{{V}_{2}}}=\frac{\frac{4}{3}r_{1}^{3}}{\frac{4}{3}r_{2}^{3}}=\frac{r_{1}^{3}}{r_{2}^{3}}\]             \[={{\left( \frac{2}{3} \right)}^{3}}=\frac{8}{27}\]


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