Metal spheres, each of radius 2 cm, are packed into a rectangular box of internal dimension 16 cm × 8 cm × 8 cm when 16 spheres are packed the box is filled with preservative liquid. Find the volume of this liquid. 
Volume of sphere 
3
= 33.50 cm3
Volume of 16 spheres = 16 × 33.50
= 536cm3
Volume of rectangle = 16cm × 8cm × 8cm
= 1024cm3
Volume of this liquid = 1024cm3 – 536cm3
= 488cm3
32