Water flows into a tank at the rate of 40 ℓ per minute. After 12 min, the tap is turned off and the tank is 0.6 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 1.4 m long, 0.4 m wide and 12 cm high. What is the minimum number of containers needed?
(a)
0.6 =
35 Let 5 u be the total volume of water when the tank is completely filled.
Volume of water in the tank
= 40 x 12
= 480 ℓ
3 u = 480
1 u = 480 ÷ 3 = 160
Volume of water to fill the tank to the brim
= 5 u - 3 u
= 2 u
= 2 x 160
= 320 ℓ
(b)
1 m = 100 cm
1.4 m = 140 cm
0.4 m = 40 cm
Volume of each container
= 140 x 40 x 12
= 67200 cm
3 Volume of water in the tank = 480 ℓ
1 ℓ = 1000 mℓ
480 ℓ = 480000 mℓ
Number of containers needed
= 480000 ÷ 67200
= 7 r 9600
Minimum number of containers needed
= 7 + 1
= 8
Answer(s): (a) 320 ℓ; (b) 8