A rectangular container measuring 84 cm by 57 cm by 32 cm was to be filled with water by two taps, L and M. Tap L which fills the tank at a rate of 5 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 7 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 container
= 84 x 57 x 32
= 153216 cm
3 1 ℓ = 1000 cm
3 5 ℓ = 5000 cm
3 Volume of water filled by Tap L
= 5000 x 7
= 35000 cm
3 Volume of water filled by Tap M
= 153216 - 35000
= 118216 cm
3 Rate in which Tap M fills the container
= 118216 ÷ 4
= 29554 cm3/min
29554 mℓ/min
= 29.554 ℓ/min
≈ 29.6 ℓ/min (Correct to 1 decimal place)
Answer(s): 29.6 ℓ/min