Respuesta :
Answer:
[tex]Joanne\: bought\: 9\: student\: tickets\:and\:6\:non-student\:tickets[/tex]
Step-by-step explanation:
[tex]Let\:x,\:y\:be\:the\:number\:of\:students\:and\:non-students,\: respectively.\\We\:have\:a\:system\:of\:equation:\left \{ {{x+y=15} \atop {12.5x+18.5y=223.5}} \right.\\\Leftrightarrow \left \{ {{x=-y+15} \atop {12.5(-y+15)+18.5y=223.5}} \right.\\\Leftrightarrow \left \{ {{x=-y+15} \atop {-12.5y+187.5+18.5y=223.5}} \right.\\\Leftrightarrow \left \{ {{x=-y+15} \atop {6y=36}}\right.\\\Leftrightarrow \left \{ {{x=-6+15=9} \atop {y=6}} \right.[/tex]