Given data
Total no.of order served=112.
Let x,y,z be the no of orders served at the school by mary,eric and shen respectively.
[tex]x+y+z=112\ldots(1)[/tex][tex]z=4x\ldots(2)[/tex][tex]y=10+x\ldots(3)[/tex]subsitute (2) and (3) equation in (1).
[tex]x+(10+x)+4x=112[/tex][tex]\begin{gathered} 6x+10=112 \\ 6x=112-10 \\ 6x=102 \\ x=\frac{102}{6} \\ x=17 \end{gathered}[/tex]susitute x=17 in equation (2),
[tex]\begin{gathered} z=4(17) \\ z=68 \end{gathered}[/tex]susitute x=17 in equation (3),
[tex]\begin{gathered} y=17+10 \\ y=27 \end{gathered}[/tex]Therefore, number of orders Mary served are 17.
number of orders Eric served are 27.
number of orders Shen served are 68