A rectangular container measuring 85 cm by 51 cm by 37 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 2 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 51 x 37
= 160395 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
= 160395 - 30000
= 130395 cm
3 Rate in which Tap Q fills the container
= 130395 ÷ 3
= 43465 cm3/min
43465 mℓ/min
= 43.465 ℓ/min
≈ 43.5 ℓ/min (Correct to 1 decimal place)
Answer(s): 43.5 ℓ/min