The figure shows an empty rectangular tank with a capacity of 45 ℓ. The tank has a height of 15 cm. Tap H filled the tank at a rate of 3.4 ℓ per minute. Tap J drained water from the tank at a rate of 1.9 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
45 ℓ = 45 x 1000 = 45000 mℓ
Base area of the tank
=
Volumeheight =
4500015 = 3000 cm
2 (b)
Volume of water that filled the tank per minute when both taps were turned on
= 3.4 - 1.9
= 1.5 ℓ
Volume of water that filled the tank in 23 minutes when both taps were turned on
= 23 x 1.5
= 34.5 ℓ
Volume of water needed to fill the tank
= 45 - 34.5
= 10.5 ℓ
Answer(s): (a) 3000 cm
2; (b) 10.5 ℓ