The figure shows an empty rectangular tank with a capacity of 34 ℓ. The tank has a height of 20 cm. Tap T filled the tank at a rate of 3.5 ℓ per minute. Tap U drained water from the tank at a rate of 1.7 ℓ per minute. Both taps were turned on for 8 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
34 ℓ = 34 x 1000 = 34000 mℓ
Base area of the tank
=
Volumeheight =
3400020 = 1700 cm
2 (b)
Volume of water that filled the tank per minute when both taps were turned on
= 3.5 - 1.7
= 1.8 ℓ
Volume of water that filled the tank in 8 minutes when both taps were turned on
= 8 x 1.8
= 14.4 ℓ
Volume of water needed to fill the tank
= 34 - 14.4
= 19.6 ℓ
Answer(s): (a) 1700 cm
2; (b) 19.6 ℓ