2 hours driving distance 405- 135=270.
Column equation: 2(x+4/5x)=405- 135.
X = 75km/h
Personally, I think there is another situation.
That is, when the distance is 135km, the two cars have already met on the way, and at this time, they have traveled 405+ 135=540 within 2 hours.
Column equation 2(x+4/5x)=405+ 135.
X =150km/h