Question

A candle flame is placed in front of a concave mirror on the principal axis such that is twice the size of the object and is inverted. If the sum of the object distance and the image distance is 72 cm, how far from the mirror is the image and what is the focal length of the mirror.

Answer 1

You left out some words after "that" in the second line. You are probably talking about the image there.

Use the lens equation and do the algebra