How many 0.75 -M main sequence stars would it take to equal the luminosity of one 15 -M star?

Answer 1

Thanks but I can't find anything ... I tried that already

Answer 2

The next place to look (gasp!) is in your text materials.

Answer 3

A 15-Mag star is 14.25 Mag higher than a 0.75-Mag star. The power ratio is
2.512^14.25 = 501,500. That is how many of the less bright stars you would need.