A rectangular tank measuring 89 cm by 60 cm by 31 cm was to be filled with water by two taps, G and H. Tap G which fills the tank at a rate of 6 ℓ per minute was first turned on for 3 minutes before Tap H was turned on as well. If the tank was filled to the brim in a total of 5 minutes from the time when Tap G was first turned on, what is the rate at which Tap H fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the tank
= 89 x 60 x 31
= 165540 cm
3 1 ℓ = 1000 cm
3 6 ℓ = 6000 cm
3 Volume of water filled by Tap G
= 6000 x 5
= 30000 cm
3 Volume of water filled by Tap H
= 165540 - 30000
= 135540 cm
3 Rate in which Tap H fills the tank
= 135540 ÷ 2
= 67770 cm3/min
67770 mℓ/min
= 67.77 ℓ/min
≈ 67.8 ℓ/min (Correct to 1 decimal place)
Answer(s): 67.8 ℓ/min