A rectangular container measuring 90 cm by 60 cm by 36 cm was to be filled with water by two taps, S and T. Tap S which fills the tank at a rate of 9 ℓ per minute was first turned on for 3 minutes before Tap T was turned on as well. If the tank was filled to the brim in a total of 7 minutes from the time when Tap S was first turned on, what is the rate at which Tap T fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the container
= 90 x 60 x 36
= 194400 cm³ 

1 ℓ = 1000 cm³ 
9 ℓ = 9000 cm³ 

Volume of water filled by Tap S
= 9000 x 7
= 63000 cm³

Volume of water filled by Tap T
= 194400 - 63000
= 131400 cm³ 

Rate in which Tap T fills the container
= 131400 ÷ 4
32850 mℓ/min
= 32.85 ℓ/min
≈ 32.9 ℓ/min (Correct to 1 decimal place)

Answer(s): 32.9 ℓ/min