Magnitude of star using Pogson's ratio

star alpha: m (magnitude) = -0.4

magnitude of star beta is 2.5 times fainter than the alpha star.

what is the magnitude of beta?

0.6

OMG nice studying princess...

I looked up the 2.5 times fainter star magnitude difference which is +1 (scale):
m 0 is brightest star in the sky and i.e.+1 would be m 1 which is 2.5 times fainter.

And m 2 would another 2.5 times fainter again than m 1.

And anything brighter than m 0 is given a minus number i.e. m -2 is 5 times brighter than m 0. there - 1 is 2.5 times brighter/

So something 2.5 times fainter i.e. +1 from -0.4 would be -0.4 + 1 = 0.6

I hope that helps explain!

if not Google 'Star Magnitude Scales

No one uses Pogson's step method any more, as it is too unreliable. Visual estimates of star brightness are made by comparing the target star with both brighter and fainter stars,