A butterfly at eye level is 16 cm in front of an plane mirror You are behind the butterfly 52 cm from the mirror What is the distance between your eye and the image of the butterfly in the mirror?

Is there a trick? If your eyes are 52cm from the plane of the mirror (which also is where the image is) then by consequence 52cm is the answer.... where the butterfly is or isn't is not relevant so long as its image is in the mirror.