A rectangular container measuring 77 cm by 50 cm by 21 cm was to be filled with water by two taps, L and M. Tap L which fills the tank at a rate of 8 ℓ per minute was first turned on for 4 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 container
= 77 x 50 x 21
= 80850 cm
3 1 ℓ = 1000 cm
3 8 ℓ = 8000 cm
3 Volume of water filled by Tap L
= 8000 x 6
= 48000 cm
3 Volume of water filled by Tap M
= 80850 - 48000
= 32850 cm
3 Rate in which Tap M fills the container
= 32850 ÷ 2
= 16425 cm3/min
16425 mℓ/min
= 16.425 ℓ/min
≈ 16.4 ℓ/min (Correct to 1 decimal place)
Answer(s): 16.4 ℓ/min