Water flows into a tank at the rate of 30 ℓ per minute. After 12 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 1.6 m long, 0.2 m wide and 12 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 12
= 360 ℓ
2 u = 360
1 u = 360 ÷ 2 = 180
Volume of water to fill the tank to the brim
= 5 u - 2 u
= 3 u
= 3 x 180
= 540 ℓ
(b)
1 m = 100 cm
1.6 m = 160 cm
0.2 m = 20 cm
Volume of each container
= 160 x 20 x 12
= 38400 cm
3 Volume of water in the tank = 360 ℓ
1 ℓ = 1000 mℓ
360 ℓ = 360000 mℓ
Number of containers needed
= 360000 ÷ 38400
= 9 r 14400
Minimum number of containers needed
= 9 + 1
= 10
Answer(s): (a) 540 ℓ; (b) 10