The figure shows an empty rectangular tank with a capacity of 54 ℓ. The tank has a height of 30 cm. Tap S filled the tank at a rate of 3.5 ℓ per minute. Tap T drained water from the tank at a rate of 1.6 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
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
= 3.5 - 1.6
= 1.9 ℓ
Volume of water that filled the tank in 8 minutes when both taps were turned on
= 8 x 1.9
= 15.2 ℓ
Volume of water needed to fill the tank
= 54 - 15.2
= 38.8 ℓ
Answer(s): (a) 1800 cm
2; (b) 38.8 ℓ