Tao Nan School P5 SA2 2007 Math Q42

A rectangular fish tank 80 cm long and 60 cm wide is filled with water from a tap which flows at a rate of 3 litres per minute. If the tap is turned off after 40 minutes, what is the height of the water level in the container?

Solution

1 minute ----- 3 litres or 3000 ml
40 minutes ----- 40 x 3000 ml
= 120 000 ml or 120 000 cubic cm

Height of water level -----

Volume = length x base x height
120 000 cubic cm = 80 cm x 60 cm x height
120 000 cubic cm = 4800 square cm x height
Height = 120 000 cubic cm divided by 4800 square cm
Height = 25 cm (Answer)