5 pungi faina + 7 pungi malai = 50 kg
7 pungi faina + 9 pungi malai = 66 kg
1 punga malai = ? kg
1 punga faina = ? kg
5f + 7m=50 /*7 35f+49m=350
7f + 9m=66 /*5 35f+45m=330 daca se scad ecuatiile
4m= 20
m=5
deci 1 punga de malai = 5kg
5f+7m=50
5f+7*5=50
5f=50-35
5f=15
f=3
deci 1 punga de faina = 3kg