1. The problem statement, all variables and given/known data Question 1 - If two stars A of luminosity 9000 and B of luminosity 90 (both relative to the Sun) appear equally bright from the Earth, how much further away is A from B? Question 2 - Star A is twice as bright as Star B, but B is twice as far away as A. Which star has the greater luminosity, and by what ratio? Question 3 - If two stars, A and B, are the same distance away, but B is 20 times more luminous than A, how much brighter will B appear than A? I could use some assistance as to how I should set these out in accordance with brightness (proportional to) Luminosity / R^2 2. Relevant equations See above 3. The attempt at a solution Question 1 - Worked out to - by moving Star A 10 times further away we have diminished the apparent brightness of Star A by a factor 10 x10 = 100 so that it now matches the brightness of Star B. Question 2 - Worked out to - Luminosity of A Luminosity of B = (½)2 x 2 = ½ This means that Star A really only has half the luminosity of Star B, but appears brighter because it is closer. Ratio 1:2 Question 3 - Worked out to 1/20th . Just need assistance to set these out correctly - and also make sure that they are correct.