The figure shows an empty rectangular tank with a capacity of 63 ℓ. The tank has a height of 30 cm. Tap T filled the tank at a rate of 3.1 ℓ per minute. Tap U drained water from the tank at a rate of 1.3 ℓ per minute. Both taps were turned on for 5 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
63 ℓ = 63 x 1000 = 63000 mℓ
Base area of the tank
=
Volumeheight =
6300030 = 2100 cm
2 (b)
Volume of water that filled the tank per minute when both taps were turned on
= 3.1 - 1.3
= 1.8 ℓ
Volume of water that filled the tank in 5 minutes when both taps were turned on
= 5 x 1.8
= 9 ℓ
Volume of water needed to fill the tank
= 63 - 9
= 54 ℓ
Answer(s): (a) 2100 cm
2; (b) 54 ℓ