A rectangular container measuring 85 cm by 59 cm by 22 cm was to be filled with water by two taps, M and N. Tap M which fills the tank at a rate of 8 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 6 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 container
= 85 x 59 x 22
= 110330 cm
3 1 ℓ = 1000 cm
3 8 ℓ = 8000 cm
3 Volume of water filled by Tap M
= 8000 x 6
= 48000 cm
3 Volume of water filled by Tap N
= 110330 - 48000
= 62330 cm
3 Rate in which Tap N fills the container
= 62330 ÷ 2
= 31165 cm3/min
31165 mℓ/min
= 31.165 ℓ/min
≈ 31.2 ℓ/min (Correct to 1 decimal place)
Answer(s): 31.2 ℓ/min