The figure shows an empty rectangular tank with a capacity of 39 ℓ. The tank has a height of 26 cm. Tap Q filled the tank at a rate of 2.4 ℓ per minute. Tap R drained water from the tank at a rate of 1.1 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
39 ℓ = 39 x 1000 = 39000 mℓ
Base area of the tank
=
Volumeheight =
3900026 = 1500 cm
2 (b)
Volume of water that filled the tank per minute when both taps were turned on
= 2.4 - 1.1
= 1.3 ℓ
Volume of water that filled the tank in 9 minutes when both taps were turned on
= 9 x 1.3
= 11.7 ℓ
Volume of water needed to fill the tank
= 39 - 11.7
= 27.3 ℓ
Answer(s): (a) 1500 cm
2; (b) 27.3 ℓ