Answer:
The attendance was 198 children, 90 students and 99 adults.
Step-by-step explanation:
We define:
c: children attendance
s: students attendance
a: adult attendance
The equation that describes the total ticket sales is:
[tex]5c+7s+12a=2808[/tex]
We also know that the children attendance doubles the adult attendance:
[tex]c=2a[/tex]
The third equation is the seating capacity, which we assume is full:
[tex]c+s+a=387[/tex]
We start by replacing variables in two of the equations:
[tex]c=2a\\\\s=387-c-a=387-2a-a=387-3a[/tex]
Then, we solve the remaining equation for a:
[tex]5c+7s+12a=2808\\\\5(2a)+7(387-3a)+12a=2808\\\\10a+(2709-21a)+12a=2808\\\\10a+12a-21a=2808-2709\\\\a=99[/tex]
Then, we solve for the other two equations:
[tex]c=2a=2*99=198\\\\s=387-3a=387-3*99=387-297=90[/tex]
The attendance was 198 children, 90 students and 99 adults.
