A rectangular tank measuring 83 cm by 60 cm by 30 cm was to be filled with water by two taps, J and K. Tap J which fills the tank at a rate of 6 ℓ per minute was first turned on for 2 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 tank
= 83 x 60 x 30
= 149400 cm
3 1 ℓ = 1000 cm
3 6 ℓ = 6000 cm
3 Volume of water filled by Tap J
= 6000 x 6
= 36000 cm
3 Volume of water filled by Tap K
= 149400 - 36000
= 113400 cm
3 Rate in which Tap K fills the tank
= 113400 ÷ 4
= 28350 cm3/min
28350 mℓ/min
= 28.35 ℓ/min
≈ 28.4 ℓ/min (Correct to 1 decimal place)
Answer(s): 28.4 ℓ/min