We have
Let x = cost of the ticket
After paying for the tickets, Mr. Herman had 125 - x
and Mr Chandra had 80 - x
Then, the equation is:
[tex]125-x=6(80-x)[/tex]So, solve for x:
[tex]\begin{gathered} 125-x=480-6x \\ 125-x+6x=480-6x+6x \\ 125+5x=480 \\ 125+5x-125=480-125 \\ 5x=355 \\ \frac{5x}{5}=\frac{355}{5} \\ x=71 \end{gathered}[/tex]The concert ticket cost is $71
Therefore, Mr. Chandra have left:
[tex]80-71=9[/tex]Answer: $9