A rectangular tank measuring 83 cm by 60 cm by 25 cm was to be filled with water by two taps, D and E. Tap D which fills the tank at a rate of 6 ℓ per minute was first turned on for 2 minutes before Tap E was turned on as well. If the tank was filled to the brim in a total of 7 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
= 83 x 60 x 25
= 124500 cm
3 1 ℓ = 1000 cm
3 6 ℓ = 6000 cm
3 Volume of water filled by Tap D
= 6000 x 7
= 42000 cm
3 Volume of water filled by Tap E
= 124500 - 42000
= 82500 cm
3 Rate in which Tap E fills the tank
= 82500 ÷ 5
= 16500 cm3/min
16500 mℓ/min
= 16.5 ℓ/min
≈ 16.5 ℓ/min (Correct to 1 decimal place)
Answer(s): 16.5 ℓ/min