A rectangular tank measuring 73 cm by 60 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 9 ℓ per minute was first turned on for 2 minutes before Tap H was turned on as well. If the tank was filled to the brim in a total of 6 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
= 73 x 60 x 21
= 91980 cm
3 1 ℓ = 1000 cm
3 9 ℓ = 9000 cm
3 Volume of water filled by Tap G
= 9000 x 6
= 54000 cm
3 Volume of water filled by Tap H
= 91980 - 54000
= 37980 cm
3 Rate in which Tap H fills the tank
= 37980 ÷ 4
= 9495 cm3/min
9495 mℓ/min
= 9.495 ℓ/min
≈ 9.5 ℓ/min (Correct to 1 decimal place)
Answer(s): 9.5 ℓ/min