Could you solve this maths problem for me?

Update: in a car with capacity 3000 litres. (there is already air in the car)

Gas cylinder is 9% nitrogen and 91% helium.
The gas cylinder size is 7.57m3 or 7570 litres.
The gas flow is 100 litres per minute.

how long would it take to achieve a 1% concentration of nitrogen in the car?
3 answers 3