Water flows into a tank at the rate of 30 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 1.7 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
= 30 x 18
= 540 ℓ
4 u = 540
1 u = 540 ÷ 4 = 135
Volume of water to fill the tank to the brim
= 5 u - 4 u
= 1 u
= 1 x 135
= 135 ℓ
(b)
1 m = 100 cm
1.7 m = 170 cm
0.4 m = 40 cm
Volume of each container
= 170 x 40 x 18
= 122400 cm
3 Volume of water in the tank = 540 ℓ
1 ℓ = 1000 mℓ
540 ℓ = 540000 mℓ
Number of containers needed
= 540000 ÷ 122400
= 4 r 50400
Minimum number of containers needed
= 4 + 1
= 5
Answer(s): (a) 135 ℓ; (b) 5