Answer:
Star A is 3.343 times hotter than star B.
Explanation:
It is known that the luminosity of a star is proportional to its effective temperature to the 4th power. This means that the ratio between the brightness of stars A and B is equal to the ratio between their temperatures to the 4th power:
[tex]125=T^4\\T=\sqrt[4]{125}\\T=3.343[/tex]
Star A is 3.343 times hotter than star B.