You could use the equation:
x = x0 + ut + (1/2)at^2
To find the answer.
Where x = the final point (1024)
x0 = the point at which the body starts slowing
u = the initial velocity (10)
t = time taken for the deceleration (more on this in a second)
a = acceleration (since this is a deceleration it's negative, -0.1)
To find the time taken for the deceleration you can use:
a = (v-u)/t
Where v = the final velocity (0 when stationary)
and rearrange to t = (v-u)/a, which gives 100, when the values are substituted. (100 = -10/-0.1)
Rearranging the first equation gives:
x0 = x - ut - (1/2)at^2
=> x0 = 1024 - 1000 + 500 = 524
I hope this helps (and that I got it right.. I still didn't quite understand the question).