A rectangular tank measuring 77 cm by 58 cm by 24 cm was to be filled with water by two taps, F and G. Tap F which fills the tank at a rate of 7 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 5 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 tank
= 77 x 58 x 24
= 107184 cm
3 1 ℓ = 1000 cm
3 7 ℓ = 7000 cm
3 Volume of water filled by Tap F
= 7000 x 5
= 35000 cm
3 Volume of water filled by Tap G
= 107184 - 35000
= 72184 cm
3 Rate in which Tap G fills the tank
= 72184 ÷ 1
= 72184 cm3/min
72184 mℓ/min
= 72.184 ℓ/min
≈ 72.2 ℓ/min (Correct to 1 decimal place)
Answer(s): 72.2 ℓ/min