A rectangular container measuring 72 cm by 51 cm by 22 cm was to be filled with water by two taps, D and E. Tap D which fills the tank at a rate of 8 ℓ per minute was first turned on for 4 minutes before Tap E was turned on as well. If the tank was filled to the brim in a total of 5 minutes from the time when Tap D was first turned on, what is the rate at which Tap E fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the container
= 72 x 51 x 22
= 80784 cm
3 1 ℓ = 1000 cm
3 8 ℓ = 8000 cm
3 Volume of water filled by Tap D
= 8000 x 5
= 40000 cm
3 Volume of water filled by Tap E
= 80784 - 40000
= 40784 cm
3 Rate in which Tap E fills the container
= 40784 ÷ 1
= 40784 cm3/min
40784 mℓ/min
= 40.784 ℓ/min
≈ 40.8 ℓ/min (Correct to 1 decimal place)
Answer(s): 40.8 ℓ/min