A hollow sphere of internal and external diameters 4 cm and 8 cm respectively is melted into a cone of base diameter 8 cm. The height of the cone is :  Pick one
A) 12 cm	B) 14 cm	C) 16 cm	D) 17 cm	E) None
Sol.   Volume of meterial in the sphere = [4/3 ∏ * {(4)³ - (2)²}] cm³   = [4/3 ∏ * 56] cm³   Let the height of the cone be h cm.   Then, 1/3 ∏ * 4 * 4 * h = [4/3 ∏ * 56]   ⇔ h = [4 * 56 / 4 * 4] = 14 cm.   Answer 14 cm
<result>B</result>
A hollow sphere of internal and external diameters 4 cm and 8 cm respectively is melted into a cone of base diameter 8 cm. The height of the cone is :