A rectangular container measuring 72 cm by 60 cm by 29 cm was to be filled with water by two taps, Z and A. Tap Z which fills the tank at a rate of 7 ℓ per minute was first turned on for 4 minutes before Tap A was turned on as well. If the tank was filled to the brim in a total of 5 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
= 72 x 60 x 29
= 125280 cm
3 1 ℓ = 1000 cm
3 7 ℓ = 7000 cm
3 Volume of water filled by Tap Z
= 7000 x 5
= 35000 cm
3 Volume of water filled by Tap A
= 125280 - 35000
= 90280 cm
3 Rate in which Tap A fills the container
= 90280 ÷ 1
= 90280 cm3/min
90280 mℓ/min
= 90.28 ℓ/min
≈ 90.3 ℓ/min (Correct to 1 decimal place)
Answer(s): 90.3 ℓ/min