Answer:
641500299.1 years
Explanation:
Stellar lifetime
[tex]\tau =10^{10}\left(\frac{M_s}{M}\right)^{2.5}[/tex]
where,
[tex]M_s[/tex] = Mass of sun
M = Mass of star = [tex]3M_s[/tex]
[tex]\tau =10^{10}\left(\frac{M_s}{3M_s}\right)^{2.5}\\\Rightarrow \tau=10^{10}\left(\frac{1}{3}\right)^{2.5}\\\Rightarrow \tau=641500299.1\ years[/tex]
The expected lifetime of a star which is 3 times the mass of the sun is 641500299.1 years
