A rectangular tank measuring 78 cm by 58 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 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 5 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
= 78 x 58 x 26
= 117624 cm
3 1 ℓ = 1000 cm
3 6 ℓ = 6000 cm
3 Volume of water filled by Tap R
= 6000 x 5
= 30000 cm
3 Volume of water filled by Tap S
= 117624 - 30000
= 87624 cm
3 Rate in which Tap S fills the tank
= 87624 ÷ 2
= 43812 cm3/min
43812 mℓ/min
= 43.812 ℓ/min
≈ 43.8 ℓ/min (Correct to 1 decimal place)
Answer(s): 43.8 ℓ/min