A rectangular tank measuring 81 cm by 54 cm by 34 cm was to be filled with water by two taps, E and F. Tap E which fills the tank at a rate of 9 ℓ per minute was first turned on for 2 minutes before Tap F was turned on as well. If the tank was filled to the brim in a total of 6 minutes from the time when Tap E was first turned on, what is the rate at which Tap F fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the tank
= 81 x 54 x 34
= 148716 cm
3 1 ℓ = 1000 cm
3 9 ℓ = 9000 cm
3 Volume of water filled by Tap E
= 9000 x 6
= 54000 cm
3 Volume of water filled by Tap F
= 148716 - 54000
= 94716 cm
3 Rate in which Tap F fills the tank
= 94716 ÷ 4
= 23679 cm3/min
23679 mℓ/min
= 23.679 ℓ/min
≈ 23.7 ℓ/min (Correct to 1 decimal place)
Answer(s): 23.7 ℓ/min