A rectangular container measuring 84 cm by 55 cm by 23 cm was to be filled with water by two taps, Z and A. Tap Z which fills the tank at a rate of 9 ℓ per minute was first turned on for 2 minutes before Tap A was turned on as well. If the tank was filled to the brim in a total of 7 minutes from the time when Tap Z was first turned on, what is the rate at which Tap A fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.
Total volume of the container
= 84 x 55 x 23
= 106260 cm
3 1 ℓ = 1000 cm
3 9 ℓ = 9000 cm
3 Volume of water filled by Tap Z
= 9000 x 7
= 63000 cm
3 Volume of water filled by Tap A
= 106260 - 63000
= 43260 cm
3 Rate in which Tap A fills the container
= 43260 ÷ 5
= 8652 cm3/min
8652 mℓ/min
= 8.652 ℓ/min
≈ 8.7 ℓ/min (Correct to 1 decimal place)
Answer(s): 8.7 ℓ/min