[tex]x-children\\\\y-adults\\\\ \left \{ {{x+y=44\ \ -->x=44-y} \atop {3*x+5*y=168}\ \ \ \ \ \ \ \ \ \ } \right. \\\\
Substitution\ method\ \\\\3(44-y)+5y=168\\\\132-3y+5y=168\\\\2y=168-132\\\\2y=36 \ \ |:2\\\y=18\\\x=44-y=44-18=26\\\\There \ were\ 26\ children.[/tex]