A rectangular tank measuring 73 cm by 60 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 6 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 tank
= 73 x 60 x 38
= 166440 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
= 166440 - 42000
= 124440 cm
3 Rate in which Tap K fills the tank
= 124440 ÷ 4
= 31110 cm3/min
31110 mℓ/min
= 31.11 ℓ/min
≈ 31.1 ℓ/min (Correct to 1 decimal place)
Answer(s): 31.1 ℓ/min