The image obtained with a converging lens is upright and 3x the length of the object. The focal length of the lens is 20cm. Calculate the object and image distances
I have absolutely no idea how to even start this question
The Attempt at a Solution
1/object + 1/image = 1/focal (lens equation )
1/ob + 1/im= 1/20
M = ob/im ( magnification formula)
I tried solving for each variable but it wasnt working...