Notăm:
a - suma primului elev ;
b - suma celui de al doilea elev .
[tex]\bf a+b=120 \Rightarrow a=120-b\ \ \ \ \ \ (1)\\ \\ 2a+5b=360\ \stackrel{(1)}{\Longrightarrow}2(120-b)+5b=360 \Rightarrow 240-2b+5b=360 \bigg|_{-240}\Rightarrow \\ \\ \Rightarrow 3b=120\bigg|_{:3} \Rightarrow b=40\ \ \ \ \ (2)\\ \\ \\ (1),\ (2) \Rightarrow a=120-40 \Rightarrow a=80[/tex]
Primul elev are 80 de lei, iar al doilea are 40 de lei .
