A rectangular tank measuring 73 cm by 55 cm by 30 cm was to be filled with water by two taps, T and U. Tap T which fills the tank at a rate of 8 ℓ per minute was first turned on for 2 minutes before Tap U was turned on as well. If the tank was filled to the brim in a total of 7 minutes from the time when Tap T was first turned on, what is the rate at which Tap U fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the tank
= 73 x 55 x 30
= 120450 cm
3 1 ℓ = 1000 cm
3 8 ℓ = 8000 cm
3 Volume of water filled by Tap T
= 8000 x 7
= 56000 cm
3 Volume of water filled by Tap U
= 120450 - 56000
= 64450 cm
3 Rate in which Tap U fills the tank
= 64450 ÷ 5
= 12890 cm3/min
12890 mℓ/min
= 12.89 ℓ/min
≈ 12.9 ℓ/min (Correct to 1 decimal place)
Answer(s): 12.9 ℓ/min