A rectangular container measuring 89 cm by 56 cm by 21 cm was to be filled with water by two taps, C and D. Tap C which fills the tank at a rate of 8 ℓ per minute was first turned on for 3 minutes before Tap D was turned on as well. If the tank was filled to the brim in a total of 6 minutes from the time when Tap C was first turned on, what is the rate at which Tap D fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the container
= 89 x 56 x 21
= 104664 cm
3 1 ℓ = 1000 cm
3 8 ℓ = 8000 cm
3 Volume of water filled by Tap C
= 8000 x 6
= 48000 cm
3 Volume of water filled by Tap D
= 104664 - 48000
= 56664 cm
3 Rate in which Tap D fills the container
= 56664 ÷ 3
= 18888 cm3/min
18888 mℓ/min
= 18.888 ℓ/min
≈ 18.9 ℓ/min (Correct to 1 decimal place)
Answer(s): 18.9 ℓ/min