The figure shows an empty rectangular tank with a capacity of 26 ℓ. The tank has a height of 20 cm. Tap D filled the tank at a rate of 3.1 ℓ per minute. Tap E drained water from the tank at a rate of 1.6 ℓ per minute. Both taps were turned on for 11 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
26 ℓ = 26 x 1000 = 26000 mℓ
Base area of the tank
=
Volumeheight =
2600020 = 1300 cm
2 (b)
Volume of water that filled the tank per minute when both taps were turned on
= 3.1 - 1.6
= 1.5 ℓ
Volume of water that filled the tank in 11 minutes when both taps were turned on
= 11 x 1.5
= 16.5 ℓ
Volume of water needed to fill the tank
= 26 - 16.5
= 9.5 ℓ
Answer(s): (a) 1300 cm
2; (b) 9.5 ℓ