MINE IS CORRECT, THE OTHER ONE HAS ERROR
Focal length , f = 15 cm
Object distance , u = - 60 cm
Image distance, v = ?
Lens formula 1/v - 1/u = 1/f
1/v - (1/-60) = 1/15
1/v +1/60 = 1/15
1/v = 1/15-1/60
1/v = ( 4 -1)/60
1/v = 3/60
V = 20 cm
behind the mirror, erect, virtual