A rectangular container measuring 77 cm by 50 cm by 34 cm was to be filled with water by two taps, K and L. Tap K which fills the tank at a rate of 6 ℓ per minute was first turned on for 3 minutes before Tap L was turned on as well. If the tank was filled to the brim in a total of 7 minutes from the time when Tap K was first turned on, what is the rate at which Tap L fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the container
= 77 x 50 x 34
= 130900 cm
3 1 ℓ = 1000 cm
3 6 ℓ = 6000 cm
3 Volume of water filled by Tap K
= 6000 x 7
= 42000 cm
3 Volume of water filled by Tap L
= 130900 - 42000
= 88900 cm
3 Rate in which Tap L fills the container
= 88900 ÷ 4
= 22225 cm3/min
22225 mℓ/min
= 22.225 ℓ/min
≈ 22.2 ℓ/min (Correct to 1 decimal place)
Answer(s): 22.2 ℓ/min