Hello, 

Given, the focal length f=+25cm(convex)

Object distance u=-25cm(left side of mirror)

from mirror formula find out the image distance as folllows

(1/u)+(1/v)=(1/f)

Substituting u and f values, we get image distance v =+12.5cm

Now velocity magnification mv=(v^2/u^2)=(12.5^2/25^2)=0.25

Therefore image velocity =mv x object velocity

=0.25 x 10=2.5cm/s

Hope this helps...