A rectangular container measuring 75 cm by 55 cm by 36 cm was to be filled with water by two taps, P and Q. Tap P which fills the tank at a rate of 8 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
= 75 x 55 x 36
= 148500 cm
3 1 ℓ = 1000 cm
3 8 ℓ = 8000 cm
3 Volume of water filled by Tap P
= 8000 x 5
= 40000 cm
3 Volume of water filled by Tap Q
= 148500 - 40000
= 108500 cm
3 Rate in which Tap Q fills the container
= 108500 ÷ 2
= 54250 cm3/min
54250 mℓ/min
= 54.25 ℓ/min
≈ 54.3 ℓ/min (Correct to 1 decimal place)
Answer(s): 54.3 ℓ/min