Answer;
= 528 km
Explanation;
Assuming the question is how far would you be from the asteroid when your relative velocity is zero.
The time taken to stop is 3250/10 = 325 secs
and your average velocity is 3250/2
So, the distance traveled is 3250 * 325 /2 = 528 km
Alternatively;
- if you started with v^2 = 2as
to get s = v^2/(2a) you get exactly the same calculation and of course the same result.