A rectangular tank measuring 89 cm by 60 cm by 27 cm was to be filled with water by two taps, M and N. Tap M which fills the tank at a rate of 6 ℓ per minute was first turned on for 4 minutes before Tap N was turned on as well. If the tank was filled to the brim in a total of 5 minutes from the time when Tap M was first turned on, what is the rate at which Tap N fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the tank
= 89 x 60 x 27
= 144180 cm
3 1 ℓ = 1000 cm
3 6 ℓ = 6000 cm
3 Volume of water filled by Tap M
= 6000 x 5
= 30000 cm
3 Volume of water filled by Tap N
= 144180 - 30000
= 114180 cm
3 Rate in which Tap N fills the tank
= 114180 ÷ 1
= 114180 cm3/min
114180 mℓ/min
= 114.18 ℓ/min
≈ 114.2 ℓ/min (Correct to 1 decimal place)
Answer(s): 114.2 ℓ/min