The figure shows an empty rectangular tank with a capacity of 60 ℓ. The tank has a height of 25 cm. Tap H filled the tank at a rate of 2.8 ℓ per minute. Tap J drained water from the tank at a rate of 1.5 ℓ per minute. Both taps were turned on for 23 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
60 ℓ = 60 x 1000 = 60000 mℓ
Base area of the tank
=
Volumeheight =
6000025 = 2400 cm
2 (b)
Volume of water that filled the tank per minute when both taps were turned on
= 2.8 - 1.5
= 1.3 ℓ
Volume of water that filled the tank in 23 minutes when both taps were turned on
= 23 x 1.3
= 29.9 ℓ
Volume of water needed to fill the tank
= 60 - 29.9
= 30.1 ℓ
Answer(s): (a) 2400 cm
2; (b) 30.1 ℓ