Question 59

Three spheres of radii 3cm, 4cm and 5cm are melted to form a new sphere. The radius of the new sphere is

Solution

Let radius of new sphere = $$r$$ cm

Volume of a sphere = $$\frac{4}{3}\pi r^3$$

=> $$\frac{4}{3}\pi r^3=(\frac{4}{3}\pi\times3^3)+(\frac{4}{3}\pi\times4^3)+(\frac{4}{3}\pi\times5^3)$$

=> $$r^3=27+64+125=216$$

=> $$r=\sqrt[3]{216}=6$$ cm

=> Ans - (A)


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