position and movement

Time needed for reaching the MAXIMUM velocity :
u=0, v=10ms^-1, a=3.3ms^-2,
By v=u+at,10=0+3.3t
t=10/3.3 s

distance of the runner's velocity change from 0 to 10ms^-1 :
By v^2-u^2=2aS, 10^2-0=2(3.3)S
S=100/6.6 m
as the maitain the velocity when she reach a maximum velocity
so, the rest of the time =(100-100/6.6) /10 s
~8.48s
So,
Finishing time=10/3.3+8.48
~11.51 s

From t = 0 to t = 10/3.3 = 3.03 s, the displacement is:

s = 0 + 3.3 x 3.032/2 = 15.2 m

Then for the remaining 84.8 m, she needs 8.48 s to finish.

Thus total time needed = 8.48 + 3.03 = 11.51 s