A rectangular tank measuring 84 cm by 53 cm by 37 cm was to be filled with water by two taps, T and U. Tap T which fills the tank at a rate of 9 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 5 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
= 84 x 53 x 37
= 164724 cm
3 1 ℓ = 1000 cm
3 9 ℓ = 9000 cm
3 Volume of water filled by Tap T
= 9000 x 5
= 45000 cm
3 Volume of water filled by Tap U
= 164724 - 45000
= 119724 cm
3 Rate in which Tap U fills the tank
= 119724 ÷ 3
= 39908 cm3/min
39908 mℓ/min
= 39.908 ℓ/min
≈ 39.9 ℓ/min (Correct to 1 decimal place)
Answer(s): 39.9 ℓ/min