In a swimming-pool $90$ m by $40$ m, $150$ men take a dip. If the average displacement of water by a man is $8$ cubic metres, what will be rise in water level ?
Let 'h' m be the rise in the water level of the swimming pool when 150 men take a dip.
Then, volume of water displaced = Displacement of water by 150 men
⇒90 m ×40 m ×h m =150×8