A rectangular container measuring 81 cm by 51 cm by 26 cm was to be filled with water by two taps, B and C. Tap B which fills the tank at a rate of 9 ℓ per minute was first turned on for 4 minutes before Tap C was turned on as well. If the tank was filled to the brim in a total of 5 minutes from the time when Tap B was first turned on, what is the rate at which Tap C fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the container
= 81 x 51 x 26
= 107406 cm
3 1 ℓ = 1000 cm
3 9 ℓ = 9000 cm
3 Volume of water filled by Tap B
= 9000 x 5
= 45000 cm
3 Volume of water filled by Tap C
= 107406 - 45000
= 62406 cm
3 Rate in which Tap C fills the container
= 62406 ÷ 1
= 62406 cm3/min
62406 mℓ/min
= 62.406 ℓ/min
≈ 62.4 ℓ/min (Correct to 1 decimal place)
Answer(s): 62.4 ℓ/min