A rectangular tank measuring 82 cm by 60 cm by 26 cm was to be filled with water by two taps, H and J. Tap H which fills the tank at a rate of 8 ℓ per minute was first turned on for 4 minutes before Tap J was turned on as well. If the tank was filled to the brim in a total of 5 minutes from the time when Tap H was first turned on, what is the rate at which Tap J fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the tank
= 82 x 60 x 26
= 127920 cm
3 1 ℓ = 1000 cm
3 8 ℓ = 8000 cm
3 Volume of water filled by Tap H
= 8000 x 5
= 40000 cm
3 Volume of water filled by Tap J
= 127920 - 40000
= 87920 cm
3 Rate in which Tap J fills the tank
= 87920 ÷ 1
= 87920 cm3/min
87920 mℓ/min
= 87.92 ℓ/min
≈ 87.9 ℓ/min (Correct to 1 decimal place)
Answer(s): 87.9 ℓ/min