The figure shows an empty rectangular tank with a capacity of 51 ℓ. The tank has a height of 17 cm. Tap C filled the tank at a rate of 3.5 ℓ per minute. Tap D drained water from the tank at a rate of 1.9 ℓ per minute. Both taps were turned on for 9 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
51 ℓ = 51 x 1000 = 51000 mℓ
Base area of the tank
=
Volumeheight =
5100017 = 3000 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 9 minutes when both taps were turned on
= 9 x 1.6
= 14.4 ℓ
Volume of water needed to fill the tank
= 51 - 14.4
= 36.6 ℓ
Answer(s): (a) 3000 cm
2; (b) 36.6 ℓ