Here we have a=0.2i+0.3j u=4i–8j and r0=6i+2j.
Using v=u+at at t=10 gives
v=4i–8j+(0.2i+0.3j)10 or
v=6i–5j ms−1
The speed is the magnitude of this velocity vector.
v=62+−52=61=7.81 ms−1
10 
62+
−5
2=
61=7.81 ms−1 