A rectangular tank measuring 170 cm by 40 cm by 100 cm is 70% filled with water. 10 identical tanks of water that are completely filled are then scooped out from it. The water level drops to 45 cm. The remaining amount of water in the tank is later poured into a container that contains 30 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 10 tanks were scooped out
= 70 - 45
= 25 cm
Volume of 10 tanks
= 170 x 40 x 25
= 170000 cm
3 Volume of 1 tank
= 170000 ÷ 10
= 17000 mℓ
= 17 ℓ
(b)
Remaining water in the tank
= 170 x 40 x 45
= 306000 cm
3 30 ℓ = 30000 mℓ
Total volume of water to drain
= 306000 + 30000
= 336000 mℓ
10 ℓ = 10000 mℓ
Time taken to drain the water
= 336000 ÷ 10000
= 33.6 min
Answer(s): (a) 17 ℓ; (b) 33.6 min