The figure shows an empty rectangular tank with a capacity of 48 ℓ. The tank has a height of 16 cm. Tap Q filled the tank at a rate of 3.4 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 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
48 ℓ = 48 x 1000 = 48000 mℓ
Base area of the tank
=
Volumeheight =
4800016 = 3000 cm
2 (b)
Volume of water that filled the tank per minute when both taps were turned on
= 3.4 - 1.8
= 1.6 ℓ
Volume of water that filled the tank in 22 minutes when both taps were turned on
= 22 x 1.6
= 35.2 ℓ
Volume of water needed to fill the tank
= 48 - 35.2
= 12.8 ℓ
Answer(s): (a) 3000 cm
2; (b) 12.8 ℓ