A rectangular container measuring 74 cm by 54 cm by 31 cm was to be filled with water by two taps, N and P. Tap N which fills the tank at a rate of 9 ℓ per minute was first turned on for 2 minutes before Tap P was turned on as well. If the tank was filled to the brim in a total of 5 minutes from the time when Tap N was first turned on, what is the rate at which Tap P fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the container
= 74 x 54 x 31
= 123876 cm
3 1 ℓ = 1000 cm
3 9 ℓ = 9000 cm
3 Volume of water filled by Tap N
= 9000 x 5
= 45000 cm
3 Volume of water filled by Tap P
= 123876 - 45000
= 78876 cm
3 Rate in which Tap P fills the container
= 78876 ÷ 3
= 26292 cm3/min
26292 mℓ/min
= 26.292 ℓ/min
≈ 26.3 ℓ/min (Correct to 1 decimal place)
Answer(s): 26.3 ℓ/min