A rectangular tank measuring 85 cm by 53 cm by 37 cm was to be filled with water by two taps, S and T. Tap S which fills the tank at a rate of 5 ℓ per minute was first turned on for 4 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 tank
= 85 x 53 x 37
= 166685 cm
3 1 ℓ = 1000 cm
3 5 ℓ = 5000 cm
3 Volume of water filled by Tap S
= 5000 x 7
= 35000 cm
3 Volume of water filled by Tap T
= 166685 - 35000
= 131685 cm
3 Rate in which Tap T fills the tank
= 131685 ÷ 3
= 43895 cm3/min
43895 mℓ/min
= 43.895 ℓ/min
≈ 43.9 ℓ/min (Correct to 1 decimal place)
Answer(s): 43.9 ℓ/min