A rectangular container measuring 79 cm by 60 cm by 37 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 3 minutes before Tap K was turned on as well. If the tank was filled to the brim in a total of 7 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
= 79 x 60 x 37
= 175380 cm
3 1 ℓ = 1000 cm
3 9 ℓ = 9000 cm
3 Volume of water filled by Tap J
= 9000 x 7
= 63000 cm
3 Volume of water filled by Tap K
= 175380 - 63000
= 112380 cm
3 Rate in which Tap K fills the container
= 112380 ÷ 4
= 28095 cm3/min
28095 mℓ/min
= 28.095 ℓ/min
≈ 28.1 ℓ/min (Correct to 1 decimal place)
Answer(s): 28.1 ℓ/min