The figure shows an empty rectangular tank with a capacity of 60 ℓ. The tank has a height of 25 cm. Tap Q filled the tank at a rate of 3.6 ℓ per minute. Tap R drained water from the tank at a rate of 1.8 ℓ per minute. Both taps were turned on for 16 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
60 ℓ = 60 x 1000 = 60000 mℓ
Base area of the tank
=
Volumeheight =
6000025 = 2400 cm
2 (b)
Volume of water that filled the tank per minute when both taps were turned on
= 3.6 - 1.8
= 1.8 ℓ
Volume of water that filled the tank in 16 minutes when both taps were turned on
= 16 x 1.8
= 28.8 ℓ
Volume of water needed to fill the tank
= 60 - 28.8
= 31.2 ℓ
Answer(s): (a) 2400 cm
2; (b) 31.2 ℓ