A sphere of radius r is inside a closed cylinder of radius r,height 2r. Sphere volume=\(4\pi r^3/3\).

(a(i)) Find the unoccupied volume when r=8 cm. [3]

(a(ii)) Find r if unoccupied volume is 36 cm³. [3]

A cone has radius 5 cm and height 12 cm. Cone curved area=\(\pi rl\).

(b(i)) Its whole surface is painted at \$0.015 per cm². Find the cost. [4]

(b(ii)) The metal cone is melted into smaller cones of radius 1.25 cm,height 3 cm. Find their number. [3]