A rectangular container measuring 85 cm by 53 cm by 32 cm was to be filled with water by two taps, P and Q. Tap P which fills the tank at a rate of 6 ℓ per minute was first turned on for 3 minutes before Tap Q was turned on as well. If the tank was filled to the brim in a total of 5 minutes from the time when Tap P was first turned on, what is the rate at which Tap Q fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the container
= 85 x 53 x 32
= 144160 cm
3 1 ℓ = 1000 cm
3 6 ℓ = 6000 cm
3 Volume of water filled by Tap P
= 6000 x 5
= 30000 cm
3 Volume of water filled by Tap Q
= 144160 - 30000
= 114160 cm
3 Rate in which Tap Q fills the container
= 114160 ÷ 2
= 57080 cm3/min
57080 mℓ/min
= 57.08 ℓ/min
≈ 57.1 ℓ/min (Correct to 1 decimal place)
Answer(s): 57.1 ℓ/min