A rectangular tank measuring 82 cm by 52 cm by 23 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 5 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
= 82 x 52 x 23
= 98072 cm
3 1 ℓ = 1000 cm
3 5 ℓ = 5000 cm
3 Volume of water filled by Tap S
= 5000 x 5
= 25000 cm
3 Volume of water filled by Tap T
= 98072 - 25000
= 73072 cm
3 Rate in which Tap T fills the tank
= 73072 ÷ 1
= 73072 cm3/min
73072 mℓ/min
= 73.072 ℓ/min
≈ 73.1 ℓ/min (Correct to 1 decimal place)
Answer(s): 73.1 ℓ/min