A rectangular tank measuring 78 cm by 59 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 6 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 6 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
= 78 x 59 x 23
= 105846 cm
3 1 ℓ = 1000 cm
3 6 ℓ = 6000 cm
3 Volume of water filled by Tap S
= 6000 x 6
= 36000 cm
3 Volume of water filled by Tap T
= 105846 - 36000
= 69846 cm
3 Rate in which Tap T fills the tank
= 69846 ÷ 3
= 23282 cm3/min
23282 mℓ/min
= 23.282 ℓ/min
≈ 23.3 ℓ/min (Correct to 1 decimal place)
Answer(s): 23.3 ℓ/min