Respuesta :
Let A be the number of advance tickets sold and S be the total number of same-day tickets sold. The total amount of tickets is A+S, then:
[tex]A+S=60[/tex]The total earnings for A advanced tickets is 30A, while the total earnings for selling S same-day tickets is 20S. Then, the total amount of money for selling A advanced tickets and S same-day tickets, is 30A+20S, then:
[tex]30A+20S=1600[/tex]Solve the system of equations to find the total amount of tickets of each type that were sold. To do so, isolate A from the first equation and then substitute the resulting expression in the second one:
[tex]\begin{gathered} A+S=60 \\ \Rightarrow A=60-S \end{gathered}[/tex][tex]\begin{gathered} 30A+20S=1600 \\ \Rightarrow30(60-S)+20S=1600 \end{gathered}[/tex]Solve for S:
[tex]\begin{gathered} \Rightarrow1800-30S+20S=1600 \\ \Rightarrow1800-10S=1600 \\ \Rightarrow-10S=1600-1800 \\ \Rightarrow-10S=-200 \\ \Rightarrow S=-\frac{200}{-10} \\ \therefore S=20 \end{gathered}[/tex]Substitute S=20 into the expression for A:
[tex]\begin{gathered} A=60-S \\ =60-20 \\ =40 \end{gathered}[/tex]Then, the solution for this system is:
[tex]\begin{gathered} A=40 \\ S=20 \end{gathered}[/tex]