A rectangular tank measuring 72 cm by 57 cm by 26 cm was to be filled with water by two taps, R and S. Tap R which fills the tank at a rate of 5 ℓ per minute was first turned on for 4 minutes before Tap S was turned on as well. If the tank was filled to the brim in a total of 6 minutes from the time when Tap R was first turned on, what is the rate at which Tap S fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the tank
= 72 x 57 x 26
= 106704 cm
3 1 ℓ = 1000 cm
3 5 ℓ = 5000 cm
3 Volume of water filled by Tap R
= 5000 x 6
= 30000 cm
3 Volume of water filled by Tap S
= 106704 - 30000
= 76704 cm
3 Rate in which Tap S fills the tank
= 76704 ÷ 2
= 38352 cm3/min
38352 mℓ/min
= 38.352 ℓ/min
≈ 38.4 ℓ/min (Correct to 1 decimal place)
Answer(s): 38.4 ℓ/min