The figure shows an empty rectangular tank with a capacity of 58 ℓ. The tank has a height of 20 cm. Tap X filled the tank at a rate of 2.8 ℓ per minute. Tap Y drained water from the tank at a rate of 1.6 ℓ per minute. Both taps were turned on for 22 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
58 ℓ = 58 x 1000 = 58000 mℓ
Base area of the tank
=
Volumeheight =
5800020 = 2900 cm
2 (b)
Volume of water that filled the tank per minute when both taps were turned on
= 2.8 - 1.6
= 1.2 ℓ
Volume of water that filled the tank in 22 minutes when both taps were turned on
= 22 x 1.2
= 26.4 ℓ
Volume of water needed to fill the tank
= 58 - 26.4
= 31.6 ℓ
Answer(s): (a) 2900 cm
2; (b) 31.6 ℓ