x= intrebari la care a raspuns corect.
z= intrebari la care a raspuns gresit.
x+b=30 b=30-x
5x-2z=122 puncte
5x-2(30-x)=122
5x-60+2x=122
7x=182
182:7=26 intrebari a raspuns corect.
30-26= 4 intrebari a raspuns gresit
Verificare:
26x5=130
4x2=8
130-8=122 ( cate puncte a obtinut Alina)