Question: By what factor has the linear size-scale of the Universe changed between when the light was emitted from the galaxy and now? The question gives the red shift z and I have the equation linear size scale = 1 / 1 + z and I know how to calculate the linear size scale. But I'm a little confused as to what the question is saying. It is asking about the factor of how much the linear size scale has changed right? So if I just give the linear size scale, the answer won't be fully correct. So I'm assuming to calculate the factor, I would need to find the initial red shift z and calculate the exponent which will give me the new linear size scale that I calculated previously? Thanks for your help.