A rectangular tank measuring 150 cm by 40 cm by 100 cm is 70% filled with water. 11 identical barrels of water that are completely filled are then scooped out from it. The water level drops to 48 cm. The remaining amount of water in the tank is later poured into a container that contains 40 litres of water. The water is then drained out through a tap found at the bottom of the container at 10 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
= 100 x 70%
= 70 cm
Difference in height when 11 barrels were scooped out
= 70 - 48
= 22 cm
Volume of 11 barrels
= 150 x 40 x 22
= 132000 cm
3 Volume of 1 barrel
= 132000 ÷ 11
= 12000 mℓ
= 12 ℓ
(b)
Remaining water in the tank
= 150 x 40 x 48
= 288000 cm
3 40 ℓ = 40000 mℓ
Total volume of water to drain
= 288000 + 40000
= 328000 mℓ
10 ℓ = 10000 mℓ
Time taken to drain the water
= 328000 ÷ 10000
= 32.8 min
Answer(s): (a) 12 ℓ; (b) 32.8 min