Water flows into a tank at the rate of 35 ℓ per minute. After 21 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 1.8 m long, 0.4 m wide and 21 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
= 35 x 21
= 735 ℓ
3 u = 735
1 u = 735 ÷ 3 = 245
Volume of water to fill the tank to the brim
= 5 u - 3 u
= 2 u
= 2 x 245
= 490 ℓ
(b)
1 m = 100 cm
1.8 m = 180 cm
0.4 m = 40 cm
Volume of each container
= 180 x 40 x 21
= 151200 cm
3 Volume of water in the tank = 735 ℓ
1 ℓ = 1000 mℓ
735 ℓ = 735000 mℓ
Number of containers needed
= 735000 ÷ 151200
= 4 r 130200
Minimum number of containers needed
= 4 + 1
= 5
Answer(s): (a) 490 ℓ; (b) 5