The figure shows an empty rectangular tank with a capacity of 54 ℓ. The tank has a height of 27 cm. Tap H filled the tank at a rate of 3.5 ℓ per minute. Tap J drained water from the tank at a rate of 1.8 ℓ per minute. Both taps were turned on for 19 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
54 ℓ = 54 x 1000 = 54000 mℓ
Base area of the tank
=
Volumeheight =
5400027 = 2000 cm
2 (b)
Volume of water that filled the tank per minute when both taps were turned on
= 3.5 - 1.8
= 1.7 ℓ
Volume of water that filled the tank in 19 minutes when both taps were turned on
= 19 x 1.7
= 32.3 ℓ
Volume of water needed to fill the tank
= 54 - 32.3
= 21.7 ℓ
Answer(s): (a) 2000 cm
2; (b) 21.7 ℓ