3) 4 inele...... 12g
8 inele......... Xg
4x=12x8
4x=96
X=96:4
X=24 g
Sau 12g+12g=24g
4)
x+y=700
Y+z=500
X+z=800
X+y=700
Y+z=500/ x(-1).
X+y-y-z=700-500
X-z=200
X-z=200
X+z=800
X-z+x+z=200+800
2x=1000
X=1000:2
X=500
X+y=700
500+y=700
Y=700-500
Y=200
X+z=800
500+z=800
Z=800-500
Z=300
Raspuns :x=500,y=200,z=300