Question

Stiind Ca 7 stilouri si 6 pixuri costa 235 de lei,iar doua stilouri si 3 pixuri costa 80 de lei,determinati ptretul unui pix si pretul unui stilou.

Answer 1

7stil+6pix=235lei
2stil+3pix=80lei    /*2

7stil+6pix=235lei - 
4stil+6pix=160 lei
_______________
3stil        =    75
1stil=75:3
1stil=25 lei

25 *2+3pix=80 lei
3pix=80-50=30
1pix=30:3
1pix=10lei

Answer 2

235-80=155(5 stilouri si 3 pixuri )
235-155=80(2 stilouri si 3 pixuri )
155-80=75 (3 stilouri )
75:3=25 ( un stilou )
25x2+3X=80
50+3X=80
3X=80-50
3X=30
X=30:3
X=10 ( un pix )