i have tried s=ut + (1/2)at^2
In 4 seconds, truck travels a distance of 0 (4) + (1/2) (1) (4)^2 = 0 + 8 = 8
now, when car starts, truck is already 8 m ahead of it.
Suppose they meet at time lapse of t seconds after car starts.
So, car travels 8 m more than the truck in t seconds...