A rectangular container 100 cm by 60 cm by 43 cm was 30% filled with water. A tap was turned on to fill it up with water at a rate of 9 ℓ/min. Every 10 seconds after the tap was turned on, an iron ball of volume 300 cm3 was added to the container. How many iron balls of the same volume would there be in the container when the container is 100% filled with water?
Percentage of volume of space to be filled
= 100% - 30%
= 70%
Volume of space in the container
= 70% x 100 x 60 x 43
=
70100 x 100 x 60 x 43
= 180600 cm
3 1 ℓ = 1000 mℓ
9 ℓ = 9 x 1000 = 9000 mℓ
Number of sets of 10 seconds in 1 min
= 60 ÷ 10
= 6
Water flowed in every 10 seconds
= 9000 ÷ 6
= 1500 mℓ
Total volume added for every 10 seconds
= 1500 + 300
= 1800 cm
3 Number of sets of 1800 cm
3= 180600 ÷ 1800
= 100 r 600
After the last iron ball is added, 600 cm
3 of water will flow into the tank so that the container is 100% filled with water.
Number of iron balls added = 100
Answer(s): 100
