A rectangular tank measuring 72 cm by 52 cm by 34 cm was to be filled with water by two taps, L and M. Tap L which fills the tank at a rate of 6 ℓ per minute was first turned on for 3 minutes before Tap M was turned on as well. If the tank was filled to the brim in a total of 6 minutes from the time when Tap L was first turned on, what is the rate at which Tap M fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the tank
= 72 x 52 x 34
= 127296 cm
3 1 ℓ = 1000 cm
3 6 ℓ = 6000 cm
3 Volume of water filled by Tap L
= 6000 x 6
= 36000 cm
3 Volume of water filled by Tap M
= 127296 - 36000
= 91296 cm
3 Rate in which Tap M fills the tank
= 91296 ÷ 3
= 30432 cm3/min
30432 mℓ/min
= 30.432 ℓ/min
≈ 30.4 ℓ/min (Correct to 1 decimal place)
Answer(s): 30.4 ℓ/min