A rectangular container measuring 83 cm by 52 cm by 30 cm was to be filled with water by two taps, E and F. Tap E which fills the tank at a rate of 9 ℓ per minute was first turned on for 2 minutes before Tap F was turned on as well. If the tank was filled to the brim in a total of 6 minutes from the time when Tap E was first turned on, what is the rate at which Tap F fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the container
= 83 x 52 x 30
= 129480 cm
3 1 ℓ = 1000 cm
3 9 ℓ = 9000 cm
3 Volume of water filled by Tap E
= 9000 x 6
= 54000 cm
3 Volume of water filled by Tap F
= 129480 - 54000
= 75480 cm
3 Rate in which Tap F fills the container
= 75480 ÷ 4
= 18870 cm3/min
18870 mℓ/min
= 18.87 ℓ/min
≈ 18.9 ℓ/min (Correct to 1 decimal place)
Answer(s): 18.9 ℓ/min