A rectangular container measuring 72 cm by 59 cm by 38 cm was to be filled with water by two taps, J and K. Tap J which fills the tank at a rate of 9 ℓ per minute was first turned on for 4 minutes before Tap K was turned on as well. If the tank was filled to the brim in a total of 6 minutes from the time when Tap J was first turned on, what is the rate at which Tap K fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the container
= 72 x 59 x 38
= 161424 cm
3 1 ℓ = 1000 cm
3 9 ℓ = 9000 cm
3 Volume of water filled by Tap J
= 9000 x 6
= 54000 cm
3 Volume of water filled by Tap K
= 161424 - 54000
= 107424 cm
3 Rate in which Tap K fills the container
= 107424 ÷ 2
= 53712 cm3/min
53712 mℓ/min
= 53.712 ℓ/min
≈ 53.7 ℓ/min (Correct to 1 decimal place)
Answer(s): 53.7 ℓ/min