The figure shows an empty rectangular tank with a capacity of 54 ℓ. The tank has a height of 30 cm. Tap B filled the tank at a rate of 2.2 ℓ per minute. Tap C drained water from the tank at a rate of 1.1 ℓ per minute. Both taps were turned on for 15 minutes and then turned off.
- What is the base area of the tank?
- After both taps were turned off, how much more water is needed to fill the tank completely? Give your answer in litres.
(a)
1 ℓ = 1000 mℓ
54 ℓ = 54 x 1000 = 54000 mℓ
Base area of the tank
=
Volumeheight =
5400030 = 1800 cm
2 (b)
Volume of water that filled the tank per minute when both taps were turned on
= 2.2 - 1.1
= 1.1 ℓ
Volume of water that filled the tank in 15 minutes when both taps were turned on
= 15 x 1.1
= 16.5 ℓ
Volume of water needed to fill the tank
= 54 - 16.5
= 37.5 ℓ
Answer(s): (a) 1800 cm
2; (b) 37.5 ℓ