One word answer please

 u = -10cm as we know object is always on left  , therefore -ve sign] 

m = -3  (as real image)

As , m = -v/u 

Therefore -v/u = -3

-v / -10 = -3 

v = 10 x (-3) 
v = - 30 cm

ii) The magnification produced by a plane mirror is +1 means then the size of the image is equal to the size of the object.

Please post other questions in different thread to get rapid assistance from our experts.

Regards