A rectangular container measuring 78 cm by 50 cm by 25 cm was to be filled with water by two taps, E and F. Tap E which fills the tank at a rate of 6 ℓ per minute was first turned on for 4 minutes before Tap F was turned on as well. If the tank was filled to the brim in a total of 5 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 container
= 78 x 50 x 25
= 97500 cm³ 

1 ℓ = 1000 cm³ 
6 ℓ = 6000 cm³ 

Volume of water filled by Tap E
= 6000 x 5
= 30000 cm³

Volume of water filled by Tap F
= 97500 - 30000
= 67500 cm³ 

Rate in which Tap F fills the container
= 67500 ÷ 1
67500 mℓ/min
= 67.5 ℓ/min
≈ 67.5 ℓ/min (Correct to 1 decimal place)

Answer(s): 67.5 ℓ/min