A rectangular container measuring 74 cm by 50 cm by 36 cm was to be filled with water by two taps, Q and R. Tap Q which fills the tank at a rate of 5 ℓ per minute was first turned on for 3 minutes before Tap R was turned on as well. If the tank was filled to the brim in a total of 5 minutes from the time when Tap Q was first turned on, what is the rate at which Tap R fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the container
= 74 x 50 x 36
= 133200 cm³ 

1 ℓ = 1000 cm³ 
5 ℓ = 5000 cm³ 

Volume of water filled by Tap Q
= 5000 x 5
= 25000 cm³

Volume of water filled by Tap R
= 133200 - 25000
= 108200 cm³ 

Rate in which Tap R fills the container
= 108200 ÷ 2
54100 mℓ/min
= 54.1 ℓ/min
≈ 54.1 ℓ/min (Correct to 1 decimal place)

Answer(s): 54.1 ℓ/min