How many persons can be accommodated in a dining hall of dimensions (20m × 15m × 4.5m), assuming that each person requires 5m3 of air?
Volume of a cuboid = Length × Breadth × Height
Volume of hall = 20 m × 15 m × 4.5 m = 1350 m3
Volume of air required by 1 person = 5 m3
No. of persons = 
=270
10