A rectangular container measuring 78 cm by 58 cm by 33 cm was to be filled with water by two taps, F and G. Tap F which fills the tank at a rate of 9 ℓ per minute was first turned on for 4 minutes before Tap G was turned on as well. If the tank was filled to the brim in a total of 7 minutes from the time when Tap F was first turned on, what is the rate at which Tap G fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the container
= 78 x 58 x 33
= 149292 cm
3 1 ℓ = 1000 cm
3 9 ℓ = 9000 cm
3 Volume of water filled by Tap F
= 9000 x 7
= 63000 cm
3 Volume of water filled by Tap G
= 149292 - 63000
= 86292 cm
3 Rate in which Tap G fills the container
= 86292 ÷ 3
= 28764 cm3/min
28764 mℓ/min
= 28.764 ℓ/min
≈ 28.8 ℓ/min (Correct to 1 decimal place)
Answer(s): 28.8 ℓ/min