A rectangular container measuring 80 cm by 59 cm by 35 cm was to be filled with water by two taps, R and S. Tap R which fills the tank at a rate of 7 ℓ per minute was first turned on for 2 minutes before Tap S was turned on as well. If the tank was filled to the brim in a total of 6 minutes from the time when Tap R was first turned on, what is the rate at which Tap S fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the container
= 80 x 59 x 35
= 165200 cm³ 

1 ℓ = 1000 cm³ 
7 ℓ = 7000 cm³ 

Volume of water filled by Tap R
= 7000 x 6
= 42000 cm³

Volume of water filled by Tap S
= 165200 - 42000
= 123200 cm³ 

Rate in which Tap S fills the container
= 123200 ÷ 4
30800 mℓ/min
= 30.8 ℓ/min
≈ 30.8 ℓ/min (Correct to 1 decimal place)

Answer(s): 30.8 ℓ/min