Answer:
7
Explanation:
[tex]The \ ratio \ of \ brightness \ of \ these \ two \ stars \ is:[/tex]
[tex]\dfrac{b_{first \ star }}{b _{second \ star }}= 2.512^{(m_{(second \ star )} - (m_{first \ star } ))}[/tex]
[tex]\dfrac{b_{first \ star }}{b _{second \ star }}= 2.512^{(0.6 - (-1.5 ))}[/tex]
[tex]\dfrac{b_{first \ star }}{b _{second \ star }}= 2.512^{(2.1)}[/tex]
[tex]\dfrac{b_{first \ star }}{b _{second \ star }}= 6.9[/tex]
[tex]\mathbf{\dfrac{b_{first \ star }}{b _{second \ star }} \simeq 7}[/tex]