The figure shows an empty rectangular tank with a capacity of 40 ℓ. The tank has a height of 25 cm. Tap F filled the tank at a rate of 3.8 ℓ per minute. Tap G drained water from the tank at a rate of 1.9 ℓ per minute. Both taps were turned on for 17 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
40 ℓ = 40 x 1000 = 40000 mℓ
Base area of the tank
=
Volumeheight =
4000025 = 1600 cm
2 (b)
Volume of water that filled the tank per minute when both taps were turned on
= 3.8 - 1.9
= 1.9 ℓ
Volume of water that filled the tank in 17 minutes when both taps were turned on
= 17 x 1.9
= 32.3 ℓ
Volume of water needed to fill the tank
= 40 - 32.3
= 7.7 ℓ
Answer(s): (a) 1600 cm
2; (b) 7.7 ℓ