.
Multiply first equation by 3; then multiply second equation by 2.
After that, subtract the second equation from the first one.
The terms with "a" will cancel each other, and you will get an equation for single unknown "s".
It is how the Elimination method works.
Solve this equation and find s, the cost of each student ticket.
Then find "a".
That's all.
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To see other similar solved problems on tickets, look in the lesson
- Using systems of equations to solve problems on tickets
in this site.