Water flows into a tank at the rate of 45 ℓ per minute. After 18 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 1.9 m long, 0.2 m wide and 18 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
= 45 x 18
= 810 ℓ
2 u = 810
1 u = 810 ÷ 2 = 405
Volume of water to fill the tank to the brim
= 5 u - 2 u
= 3 u
= 3 x 405
= 1215 ℓ
(b)
1 m = 100 cm
1.9 m = 190 cm
0.2 m = 20 cm
Volume of each container
= 190 x 20 x 18
= 68400 cm
3 Volume of water in the tank = 810 ℓ
1 ℓ = 1000 mℓ
810 ℓ = 810000 mℓ
Number of containers needed
= 810000 ÷ 68400
= 11 r 57600
Minimum number of containers needed
= 11 + 1
= 12
Answer(s): (a) 1215 ℓ; (b) 12