A solid cone of height 24 cm and radius of its base 8 cm is melted to form a solid cylinder of radius 6 cm and height 6 cm. In the whole process what percent of material is wasted?

Height of cone = $$H=24$$ cm and radius of cone = $$R=8$$ cm

=> Volume of cone = $$\frac{1}{3}\pi R^2H$$

= $$\frac{1}{3}\pi (8)^2\times24$$

= $$\pi\times64\times8=512\pi$$ $$cm^3$$

Height of cyinder = $$h=6$$ cm and radius = $$r=6$$ cm

=> Volume of cylinder = $$\pi r^2h$$

= $$\pi\times(6)^2\times6=216\pi$$ $$cm^3$$

$$\therefore$$ % material wasted = $$\frac{(512-216)}{512}\times100$$

= $$\frac{37}{64}\times100=57.8\%$$

=> Ans - (C)