A rectangular container measuring 78 cm by 59 cm by 38 cm was to be filled with water by two taps, Z and A. Tap Z which fills the tank at a rate of 6 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
= 78 x 59 x 38
= 174876 cm
3 1 ℓ = 1000 cm
3 6 ℓ = 6000 cm
3 Volume of water filled by Tap Z
= 6000 x 5
= 30000 cm
3 Volume of water filled by Tap A
= 174876 - 30000
= 144876 cm
3 Rate in which Tap A fills the container
= 144876 ÷ 2
= 72438 cm3/min
72438 mℓ/min
= 72.438 ℓ/min
≈ 72.4 ℓ/min (Correct to 1 decimal place)
Answer(s): 72.4 ℓ/min