A rectangular tank measuring 73 cm by 50 cm by 31 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 4 minutes before Tap Q was turned on as well. If the tank was filled to the brim in a total of 6 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 tank
= 73 x 50 x 31
= 113150 cm
3 1 ℓ = 1000 cm
3 8 ℓ = 8000 cm
3 Volume of water filled by Tap P
= 8000 x 6
= 48000 cm
3 Volume of water filled by Tap Q
= 113150 - 48000
= 65150 cm
3 Rate in which Tap Q fills the tank
= 65150 ÷ 2
= 32575 cm3/min
32575 mℓ/min
= 32.575 ℓ/min
≈ 32.6 ℓ/min (Correct to 1 decimal place)
Answer(s): 32.6 ℓ/min