A rectangular container measuring 87 cm by 56 cm by 27 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 2 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
= 87 x 56 x 27
= 131544 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
= 131544 - 45000
= 86544 cm
3 Rate in which Tap C fills the container
= 86544 ÷ 3
= 28848 cm3/min
28848 mℓ/min
= 28.848 ℓ/min
≈ 28.8 ℓ/min (Correct to 1 decimal place)
Answer(s): 28.8 ℓ/min