A rectangular container measuring 88 cm by 55 cm by 36 cm was to be filled with water by two taps, C and D. Tap C which fills the tank at a rate of 7 ℓ per minute was first turned on for 3 minutes before Tap D was turned on as well. If the tank was filled to the brim in a total of 7 minutes from the time when Tap C was first turned on, what is the rate at which Tap D fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the container
= 88 x 55 x 36
= 174240 cm
3 1 ℓ = 1000 cm
3 7 ℓ = 7000 cm
3 Volume of water filled by Tap C
= 7000 x 7
= 49000 cm
3 Volume of water filled by Tap D
= 174240 - 49000
= 125240 cm
3 Rate in which Tap D fills the container
= 125240 ÷ 4
= 31310 cm3/min
31310 mℓ/min
= 31.31 ℓ/min
≈ 31.3 ℓ/min (Correct to 1 decimal place)
Answer(s): 31.3 ℓ/min