A rectangular container measuring 81 cm by 50 cm by 21 cm was to be filled with water by two taps, G and H. Tap G which fills the tank at a rate of 5 ℓ per minute was first turned on for 4 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 container
= 81 x 50 x 21
= 85050 cm
3 1 ℓ = 1000 cm
3 5 ℓ = 5000 cm
3 Volume of water filled by Tap G
= 5000 x 5
= 25000 cm
3 Volume of water filled by Tap H
= 85050 - 25000
= 60050 cm
3 Rate in which Tap H fills the container
= 60050 ÷ 1
= 60050 cm3/min
60050 mℓ/min
= 60.05 ℓ/min
≈ 60.1 ℓ/min (Correct to 1 decimal place)
Answer(s): 60.1 ℓ/min