The figure shows an empty rectangular tank with a capacity of 45 ℓ. The tank has a height of 25 cm. Tap M filled the tank at a rate of 3.2 ℓ per minute. Tap N drained water from the tank at a rate of 1.4 ℓ per minute. Both taps were turned on for 6 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
45 ℓ = 45 x 1000 = 45000 mℓ
Base area of the tank
=
Volumeheight =
4500025 = 1800 cm
2 (b)
Volume of water that filled the tank per minute when both taps were turned on
= 3.2 - 1.4
= 1.8 ℓ
Volume of water that filled the tank in 6 minutes when both taps were turned on
= 6 x 1.8
= 10.8 ℓ
Volume of water needed to fill the tank
= 45 - 10.8
= 34.2 ℓ
Answer(s): (a) 1800 cm
2; (b) 34.2 ℓ