The figure shows an empty rectangular tank with a capacity of 54 ℓ. The tank has a height of 20 cm. Tap U filled the tank at a rate of 3.5 ℓ per minute. Tap V drained water from the tank at a rate of 1.9 ℓ per minute. Both taps were turned on for 5 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 =
5400020 = 2700 cm
2 (b)
Volume of water that filled the tank per minute when both taps were turned on
= 3.5 - 1.9
= 1.6 ℓ
Volume of water that filled the tank in 5 minutes when both taps were turned on
= 5 x 1.6
= 8 ℓ
Volume of water needed to fill the tank
= 54 - 8
= 46 ℓ
Answer(s): (a) 2700 cm
2; (b) 46 ℓ