When can hfc-134a become combustible in a mobile air conditioning system?

The  mixture  of  HFc-134a with  high  concentration  of  air  at  raised  pressure    can  become  combustible  in  presence  of  a  ignition  source,  that  is  oxygen  enriched  environment.Thus  at  high  pressure  in a mobile  air  condition   led   to   combustible  of HFC-134a.

23s

Explanation:

s=ut+1/2at^2

the distance (s) is 400, initial velocity (u) is 0, acceleration (a) is 1.5 therefore

400=0t+1/2(1.5)t^2

400/0.75=0.75t^2/0.75

t^2=√533.33

t=23s

I hope this helps and sorry if it's wrong