A cubical tank of edge 30 cm contained some water to a height of 12 cm.
- Find the volume of water in the tank at first.
- A tap was then turned on for 19 minutes to fill the tank with water at a rate of 0.7 ℓ per minute. How much more water was needed to fill the tank to the brim when the tap was turned off? Leave your answer in litres.
(a)
Volume of water in the tank at first
= 30 x 30 x 12
= 10800 cm
3
(b)
Remaining height of the tank not filled with water before the tap was turned on
= 30 - 12
= 18 cm
Volume of water needed to fill the tank
= 30 x 30 x 18
= 16200 cm³
1 ℓ = 1000 mℓ
0.7 ℓ = 0.7 x 1000 = 700 mℓ
Volume of water filled by the tap in 19 min
= 19 x 700
= 13300 cm
3Volume of more water needed to fill the tank to the brim when the tap was turned off
= 16200 - 13300
= 2900 cm
3
2900 mℓ = 2900 ÷ 1000 = 2.9 ℓ
Volume of more water to fill the tank = 2.9 ℓ
Answer(s): (a) 10800 cm
3; (b) 2.9 ℓ