A rectangular tank measuring 77 cm by 55 cm by 32 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 6 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 tank
= 77 x 55 x 32
= 135520 cm
3 1 ℓ = 1000 cm
3 8 ℓ = 8000 cm
3 Volume of water filled by Tap D
= 8000 x 6
= 48000 cm
3 Volume of water filled by Tap E
= 135520 - 48000
= 87520 cm
3 Rate in which Tap E fills the tank
= 87520 ÷ 2
= 43760 cm3/min
43760 mℓ/min
= 43.76 ℓ/min
≈ 43.8 ℓ/min (Correct to 1 decimal place)
Answer(s): 43.8 ℓ/min