Let's set up variables and equations for things that we know from the question, with a standing for advance tickets, and s standing for same day tickets.
[tex]40a + 30s = 1250[/tex]
[tex]a + s = 35[/tex]
Let's solve it through substitution. Isolate either variable, a or s. I'll choose to isolate a. Subtract s from both sides.
[tex]a = -s + 35[/tex]
Plug the new knowledge into the first equation, since we now know the value of a
[tex]40(-s +35) + 30s = 1250[/tex].
Distribute the 40 to the -s and 35
[tex]-40s + 1400 + 30s = 1250[/tex]
Combine the negative and positive s
[tex]-10s + 1400 = 1250[/tex]
Subtract 1400 from both sides.
[tex]-10s = -150[/tex]
Divide both sides by -10
[tex]s = 15 [/tex]
The total price of an advanced ticket and same-day ticket is 35, and we know the value of a same-day ticket, so the price of an advance ticket must be 20.
The final answers are:
advanced ticket = 20
same day ticket = 15