Water flows into a tank at the rate of 50 ℓ per minute. After 21 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 1.8 m long, 0.1 m wide and 21 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
= 50 x 21
= 1050 ℓ
2 u = 1050
1 u = 1050 ÷ 2 = 525
Volume of water to fill the tank to the brim
= 5 u - 2 u
= 3 u
= 3 x 525
= 1575 ℓ
(b)
1 m = 100 cm
1.8 m = 180 cm
0.1 m = 10 cm
Volume of each container
= 180 x 10 x 21
= 37800 cm
3 Volume of water in the tank = 1050 ℓ
1 ℓ = 1000 mℓ
1050 ℓ = 1050000 mℓ
Number of containers needed
= 1050000 ÷ 37800
= 27 r 29400
Minimum number of containers needed
= 27 + 1
= 28
Answer(s): (a) 1575 ℓ; (b) 28