Here, `R_(1)=+12cm, R_(2)=oo, mu_(p)=1.5, mu_(a)=1 ,` therefore
Focal length of the lens, `(1)/(f_(1))=(1.5-1)[(1)/(12)-(1)/(oo)]`
or `f_(1)=24 cm`
The plane side of the lens is silvered, focal length of the mirror
`f_(m)=(R_(2))/(2)=(oo)/(2)=oo`
Therefore, effective focal length of the silvered lens is
`(1)/(f_(e))=(1)/(f_(m))-(2)/(f_(1)) orf_(e)= -12cm`
The object is placed 24 cm in front of the lens.
`u=-24cm, f=-12cm`
And from the mirror Eq. (i), we have
`(1)/(v)+(1)/(u)=(1)/(f)` (i)
or `v=-24 cm`
The final image is formed on the object itself. The behavior is like that of a concave mirror.