Advance tickets: $30
Same-day tickets: $20
Tickets sold: 55
Total money: $1300
Let us say that a represents the number of advance tickets sold, and s is the number of same-day tickets sold. Then, from the total number of tickets sold:
[tex]a+s=55...(1)[/tex]And for the total income:
[tex]\begin{gathered} 30a+20s=1300 \\ 3a+2s=130...(2) \end{gathered}[/tex]From (1):
[tex]a=55-s...(1^{\prime})[/tex]Using this result on (2):
[tex]\begin{gathered} 3(55-s)+2s=130 \\ 165-3s+2s=130 \\ \Rightarrow s=35 \end{gathered}[/tex]Using this on (1'):
[tex]\begin{gathered} a=55-35 \\ \Rightarrow a=20 \end{gathered}[/tex]Number of advance tickets sold: 20
Number of same-day tickets sold: 35