Water flows into a tank at the rate of 45 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 1.7 m long, 0.2 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
= 45 x 21
= 945 ℓ
3 u = 945
1 u = 945 ÷ 3 = 315
Volume of water to fill the tank to the brim
= 5 u - 3 u
= 2 u
= 2 x 315
= 630 ℓ
(b)
1 m = 100 cm
1.7 m = 170 cm
0.2 m = 20 cm
Volume of each container
= 170 x 20 x 21
= 71400 cm
3 Volume of water in the tank = 945 ℓ
1 ℓ = 1000 mℓ
945 ℓ = 945000 mℓ
Number of containers needed
= 945000 ÷ 71400
= 13 r 16800
Minimum number of containers needed
= 13 + 1
= 14
Answer(s): (a) 630 ℓ; (b) 14