A rectangular tank 40 cm long, 20 cm wide and 39 cm high was
35 filled with water.
- What was the volume of the water in the tank in litres?
- A tap was used to drain the water from the tank at a rate of 4 ℓ per minute. The tap was turned off when the tank was 13 filled with water. How long did it take to drain the water?
(a)
Volume of water in the tank
=
35 x 40 x 20 x 39
= 18720 cm
3 1000 mℓ = 1 ℓ
18720 mℓ = 18720 ÷ 1000 = 18.72 ℓ
Volume of water in the tank = 18.72 ℓ
(b)
Volume of water in the tank in the end
=
13 x 40 x 20 x 39
= 10400 cm
3 Volume of water that was drained from the tank
= 18720 - 10400
= 8320 cm
34 ℓ = 4 x 1000 = 4000 mℓ
Time taken for the tap to drain the water
= 8320 ÷ 4000
= 2.08 min
Answer(s): (a) 18.72 ℓ; (b) 2.08 min