You must go to the water park for 8 days to make buying the season pass worth it.
Explanation
Suppose, the number of days you must go to the water park is [tex]x[/tex]
Admission for the park is 17.50 per day. So, the total cost for [tex]x[/tex] days will be: [tex]17.50x[/tex]
Given that, the season pass cost 125. So, the equation will be.....
[tex]17.50x=125\\ \\ x=\frac{125}{17.50}=7.142...\\ \\ x \approx 8[/tex]
(As the number of days can't be in decimal)
So, you must go to the water park for 8 days to make buying the season pass worth it.