Too bad, the velocity got dropped out of your problem.
ill guess you tried to say
” if the velocity is v, the stopping distance is s”
then you asked, “if the velocity is nv, what is the stopping distance”
It depends on whether “stopping distance = “braking distance” or if it also includes “reaction distance”.
ill answer the easier question: if braking distance at velocity v is s, what is braking distance starts no at nv?
The physics answer is that the braking distance is proportional to the velocity squared.
So distance is n2s.