A rectangular container measuring 89 cm by 55 cm by 23 cm was to be filled with water by two taps, X and Y. Tap X which fills the tank at a rate of 9 ℓ per minute was first turned on for 4 minutes before Tap Y was turned on as well. If the tank was filled to the brim in a total of 5 minutes from the time when Tap X was first turned on, what is the rate at which Tap Y fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the container
= 89 x 55 x 23
= 112585 cm
3 1 ℓ = 1000 cm
3 9 ℓ = 9000 cm
3 Volume of water filled by Tap X
= 9000 x 5
= 45000 cm
3 Volume of water filled by Tap Y
= 112585 - 45000
= 67585 cm
3 Rate in which Tap Y fills the container
= 67585 ÷ 1
= 67585 cm3/min
67585 mℓ/min
= 67.585 ℓ/min
≈ 67.6 ℓ/min (Correct to 1 decimal place)
Answer(s): 67.6 ℓ/min