Lens formula,

1/v - 1/u = 1/f

where,

v = image distance from lens

u = object distance from lens

f = focal length

here ,

f = 30 cm { for convex lens f is positive }

v = 60cm

1/60 - 1/u = 1/30 -> 1/60 - 1/30 = 1/u -> -1/60 = 1/u -> u = -60 cm

hence, object distance also 60cm but left side of convex lens . in which position of image is right side.

magnification = ( image distance )/(object distance ) = 60/(-60) = -1

it means height of image = height of object . but both lies just opposite sides of lens .