A rectangular tank measuring 87 cm by 56 cm by 23 cm was to be filled with water by two taps, R and S. Tap R which fills the tank at a rate of 6 ℓ per minute was first turned on for 3 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
= 87 x 56 x 23
= 112056 cm
3 1 ℓ = 1000 cm
3 6 ℓ = 6000 cm
3 Volume of water filled by Tap R
= 6000 x 6
= 36000 cm
3 Volume of water filled by Tap S
= 112056 - 36000
= 76056 cm
3 Rate in which Tap S fills the tank
= 76056 ÷ 3
= 25352 cm3/min
25352 mℓ/min
= 25.352 ℓ/min
≈ 25.4 ℓ/min (Correct to 1 decimal place)
Answer(s): 25.4 ℓ/min