We have the next information
7.75 admission
0.50 ride
you have 15 that is the limit
The inequality will be
[tex]7.75+0.50x\le\text{ 15}[/tex]where x is the number of rides you can do
Using the inequality we can calculate the number of rides, we need to clear x
[tex]\begin{gathered} 0.50x\le15-7.75 \\ 0.50x\le7.25 \\ x\le\frac{7.25}{0.50} \\ x\le14.5 \end{gathered}[/tex]the maximum number of rides is 14 because we can't do a half ride