The Luminosity of two stars with same brightness but at different PC away Stars A and B are both equally bright as seen from Earth, but A is 120 pc away while B is 24 pc away. Which star has the greater luminosity? How many times brighter is it?
The absolute luminosity of A is bigger than B. Like two lamps.
$$\frac{120}{24}=5,$$
so A is five times farther B, but as the luminosity decays with the square of the distance, then  A is $5^{2}=25$ times more luminous.