Water flows into a tank at the rate of 40 ℓ per minute. After 20 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 1.9 m long, 0.3 m wide and 20 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
= 40 x 20
= 800 ℓ
2 u = 800
1 u = 800 ÷ 2 = 400
Volume of water to fill the tank to the brim
= 5 u - 2 u
= 3 u
= 3 x 400
= 1200 ℓ
(b)
1 m = 100 cm
1.9 m = 190 cm
0.3 m = 30 cm
Volume of each container
= 190 x 30 x 20
= 114000 cm
3 Volume of water in the tank = 800 ℓ
1 ℓ = 1000 mℓ
800 ℓ = 800000 mℓ
Number of containers needed
= 800000 ÷ 114000
= 7 r 2000
Minimum number of containers needed
= 7 + 1
= 8
Answer(s): (a) 1200 ℓ; (b) 8