A rectangular container measuring 84 cm by 56 cm by 20 cm was to be filled with water by two taps, Z and A. Tap Z which fills the tank at a rate of 5 ℓ per minute was first turned on for 3 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
= 84 x 56 x 20
= 94080 cm
3 1 ℓ = 1000 cm
3 5 ℓ = 5000 cm
3 Volume of water filled by Tap Z
= 5000 x 5
= 25000 cm
3 Volume of water filled by Tap A
= 94080 - 25000
= 69080 cm
3 Rate in which Tap A fills the container
= 69080 ÷ 2
= 34540 cm3/min
34540 mℓ/min
= 34.54 ℓ/min
≈ 34.5 ℓ/min (Correct to 1 decimal place)
Answer(s): 34.5 ℓ/min