The given information is:
- Cost of each child ticket: $5.10
- Cost of each adult ticket: $9.80
- They sold 3 times as many adult tickets as child tickets
- The total sales were $1311.00
So, we can express this situation in the form of algebraic equations:
Let's set "A" as the number of adult tickets sold, and "C" as the number of child tickets sold, so:
[tex]A=3C\text{ Equation 1}[/tex]Now, the total sales are given by:
[tex]5.10*C+9.80*A=1311.00\text{ Equation 2}[/tex]Replace equation 1 into equation 2 and solve for C:
[tex]\begin{gathered} 5.10C+9.80(3C)=1311.00 \\ 5.10C+29.40C=1311.00 \\ 34.50C=1311.00 \\ C=\frac{1311.00}{3.50} \\ C=38 \end{gathered}[/tex]Now, replace C-value into equation 1 and solve for A:
[tex]\begin{gathered} A=3*38 \\ A=114 \end{gathered}[/tex]Then, there were sold 38 child tickets and 114 adult tickets.