A rectangular container measuring 77 cm by 57 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 4 minutes before Tap F was turned on as well. If the tank was filled to the brim in a total of 5 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
= 77 x 57 x 30
= 131670 cm
3 1 ℓ = 1000 cm
3 9 ℓ = 9000 cm
3 Volume of water filled by Tap E
= 9000 x 5
= 45000 cm
3 Volume of water filled by Tap F
= 131670 - 45000
= 86670 cm
3 Rate in which Tap F fills the container
= 86670 ÷ 1
= 86670 cm3/min
86670 mℓ/min
= 86.67 ℓ/min
≈ 86.7 ℓ/min (Correct to 1 decimal place)
Answer(s): 86.7 ℓ/min