The figure shows an empty rectangular tank with a capacity of 44 ℓ. The tank has a height of 22 cm. Tap C filled the tank at a rate of 3 ℓ per minute. Tap D drained water from the tank at a rate of 1.4 ℓ per minute. Both taps were turned on for 8 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
44 ℓ = 44 x 1000 = 44000 mℓ
Base area of the tank
=
Volumeheight =
4400022 = 2000 cm
2 (b)
Volume of water that filled the tank per minute when both taps were turned on
= 3 - 1.4
= 1.6 ℓ
Volume of water that filled the tank in 8 minutes when both taps were turned on
= 8 x 1.6
= 12.8 ℓ
Volume of water needed to fill the tank
= 44 - 12.8
= 31.2 ℓ
Answer(s): (a) 2000 cm
2; (b) 31.2 ℓ