Banking Quantitative Aptitude Sample Paper Quantitative Aptitude Sample Paper-41

  • question_answer
    A metallic sphere of radius 12 cm is melted into three smaller spheres. If the radii of two smaller spheres are 6 cm and 8 cm, the radius of the third is

    A) 14 cm              

    B) 16 cm

    C) 10 cm  

    D) 12 cm

    Correct Answer: C

    Solution :

    Let radius of the third sphere be r cm.
    Then, \[\frac{4}{3}\pi \times \,\,{{(12)}^{3}}=\frac{4}{3}\pi \times {{(6)}^{3}}+\frac{4}{3}\pi \times {{(8)}^{3}}+\frac{4}{3}\pi {{r}^{3}}\]
    \[\Rightarrow \]   \[{{(12)}^{3}}={{(6)}^{3}}+{{(8)}^{3}}+{{r}^{3}}\]
    \[\Rightarrow \]   \[{{r}^{3}}=1728-216-512\]\[\Rightarrow \]\[{{r}^{3}}=1000\]
    \[\therefore \]      \[r=10\,\,cm\]


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