Given that, focal length, f= 20 cm
object distance, u= -30 cm
Now, 1/f= 1/v-1/u
v= 60 cm
So the image will be real and on the opposite side as the object.
Image height, v/u=I/O
60/(-30) = I/5
I= -10 cm
The negative sign indicates that the image will be inverted.