A rectangular tank measuring 160 cm by 60 cm by 120 cm is 40% filled with water. 12 identical jars of water that are completely filled are then scooped out from it. The water level drops to 43 cm. The remaining amount of water in the tank is later poured into a container that contains 50 litres of water. The water is then drained out through a tap found at the bottom of the container at 20 litres per minute.
- What is the capacity of each pail? Answer in litres.
- How long did it take to drain the water from the container completely? Answer in terms of min.
(a)
Original height of water in the tank
= 120 x 40%
= 48 cm
Difference in height when 12 jars were scooped out
= 48 - 43
= 5 cm
Volume of 12 jars
= 160 x 60 x 5
= 48000 cm
3 Volume of 1 jar
= 48000 ÷ 12
= 4000 mℓ
= 4 ℓ
(b)
Remaining water in the tank
= 160 x 60 x 43
= 412800 cm
3 50 ℓ = 50000 mℓ
Total volume of water to drain
= 412800 + 50000
= 462800 mℓ
20 ℓ = 20000 mℓ
Time taken to drain the water
= 462800 ÷ 20000
= 23.14 min
Answer(s): (a) 4 ℓ; (b) 23.14 min