The figure shows an empty rectangular tank with a capacity of 35 ℓ. The tank has a height of 25 cm. Tap C filled the tank at a rate of 3 ℓ per minute. Tap D drained water from the tank at a rate of 1.7 ℓ per minute. Both taps were turned on for 10 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
35 ℓ = 35 x 1000 = 35000 mℓ
Base area of the tank
=
Volumeheight =
3500025 = 1400 cm
2 (b)
Volume of water that filled the tank per minute when both taps were turned on
= 3 - 1.7
= 1.3 ℓ
Volume of water that filled the tank in 10 minutes when both taps were turned on
= 10 x 1.3
= 13 ℓ
Volume of water needed to fill the tank
= 35 - 13
= 22 ℓ
Answer(s): (a) 1400 cm
2; (b) 22 ℓ