A rectangular tank measuring 74 cm by 58 cm by 39 cm was to be filled with water by two taps, C and D. Tap C which fills the tank at a rate of 5 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 6 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 tank
= 74 x 58 x 39
= 167388 cm
3 1 ℓ = 1000 cm
3 5 ℓ = 5000 cm
3 Volume of water filled by Tap C
= 5000 x 6
= 30000 cm
3 Volume of water filled by Tap D
= 167388 - 30000
= 137388 cm
3 Rate in which Tap D fills the tank
= 137388 ÷ 3
= 45796 cm3/min
45796 mℓ/min
= 45.796 ℓ/min
≈ 45.8 ℓ/min (Correct to 1 decimal place)
Answer(s): 45.8 ℓ/min