A rectangular tank measuring 73 cm by 54 cm by 26 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 4 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 tank
= 73 x 54 x 26
= 102492 cm
3 1 ℓ = 1000 cm
3 6 ℓ = 6000 cm
3 Volume of water filled by Tap J
= 6000 x 7
= 42000 cm
3 Volume of water filled by Tap K
= 102492 - 42000
= 60492 cm
3 Rate in which Tap K fills the tank
= 60492 ÷ 3
= 20164 cm3/min
20164 mℓ/min
= 20.164 ℓ/min
≈ 20.2 ℓ/min (Correct to 1 decimal place)
Answer(s): 20.2 ℓ/min