Water flows into a tank at the rate of 40 ℓ per minute. After 18 min, the tap is turned off and the tank is 0.8 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 1.3 m long, 0.4 m wide and 18 cm high. What is the minimum number of containers needed?
(a)
0.8 =
45 Let 5 u be the total volume of water when the tank is completely filled.
Volume of water in the tank
= 40 x 18
= 720 ℓ
4 u = 720
1 u = 720 ÷ 4 = 180
Volume of water to fill the tank to the brim
= 5 u - 4 u
= 1 u
= 1 x 180
= 180 ℓ
(b)
1 m = 100 cm
1.3 m = 130 cm
0.4 m = 40 cm
Volume of each container
= 130 x 40 x 18
= 93600 cm
3 Volume of water in the tank = 720 ℓ
1 ℓ = 1000 mℓ
720 ℓ = 720000 mℓ
Number of containers needed
= 720000 ÷ 93600
= 7 r 64800
Minimum number of containers needed
= 7 + 1
= 8
Answer(s): (a) 180 ℓ; (b) 8