Answer
39 child tickets were sold that day
Step-by-step explanation
Variables
• x: child tickets sold
,• y: adult tickets sold
Given that four times as many adult tickets as child tickets were sold, then:
[tex]y=4x[/tex]If 1 child ticket cost $5.70, then x child tickets will cost 5.7x dollars.
If 1 adult ticket cost $9.20, then y adult tickets will cost 9.2y dollars.
Given that the theater sold tickets for $1657.50, then:
[tex]5.7x+9.2y=1657.5[/tex]Substituting the first equation into the second one and solving for x:
[tex]\begin{gathered} 5.7x+9.2(4x)=1,657.5 \\ 5.7x+36.8x=1,657.5 \\ 42.5x=1,657.5 \\ \frac{42.5x}{42.5}=\frac{1,657.5}{42.5} \\ x=39 \end{gathered}[/tex]