A rectangular tank measuring 86 cm by 50 cm by 29 cm was to be filled with water by two taps, Y and Z. Tap Y which fills the tank at a rate of 8 ℓ per minute was first turned on for 4 minutes before Tap Z was turned on as well. If the tank was filled to the brim in a total of 7 minutes from the time when Tap Y was first turned on, what is the rate at which Tap Z fills the tank? Give your answer in ℓ per minute correct to 1 decimal place.

3 m

(3 m)

(3 m)