A rectangular tank measuring 82 cm by 51 cm by 23 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 6 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 tank
= 82 x 51 x 23
= 96186 cm
3 1 ℓ = 1000 cm
3 6 ℓ = 6000 cm
3 Volume of water filled by Tap K
= 6000 x 6
= 36000 cm
3 Volume of water filled by Tap L
= 96186 - 36000
= 60186 cm
3 Rate in which Tap L fills the tank
= 60186 ÷ 3
= 20062 cm3/min
20062 mℓ/min
= 20.062 ℓ/min
≈ 20.1 ℓ/min (Correct to 1 decimal place)
Answer(s): 20.1 ℓ/min