Water flows into a tank at the rate of 30 ℓ per minute. After 20 min, the tap is turned off and the tank is 0.4 filled with water.
- How much more water is needed to fill it to the brim?
- The water in the tank is then poured into containers each 1.5 m long, 0.5 m wide and 20 cm high. What is the minimum number of containers needed?
(a)
0.4 =
25 Let 5 u be the total volume of water when the tank is completely filled.
Volume of water in the tank
= 30 x 20
= 600 ℓ
2 u = 600
1 u = 600 ÷ 2 = 300
Volume of water to fill the tank to the brim
= 5 u - 2 u
= 3 u
= 3 x 300
= 900 ℓ
(b)
1 m = 100 cm
1.5 m = 150 cm
0.5 m = 50 cm
Volume of each container
= 150 x 50 x 20
= 150000 cm
3 Volume of water in the tank = 600 ℓ
1 ℓ = 1000 mℓ
600 ℓ = 600000 mℓ
Number of containers needed
= 600000 ÷ 150000
= 4 r 0
Minimum number of containers needed
= 4 + 1
= 5
Answer(s): (a) 900 ℓ; (b) 5