Răspuns :
a+b+c=1680
a+2b+3c=3220
a+2b=1540
1540+3c=3220
3c=3220-1540
3c=1680
c=1680:3
c=560
a+b+560=1680
a+b=1680-560
a+b=1120
a+2b=1540 -
a+ b=1120
........................
b = 420
a+420=1120
a=1120-420
a=700
V: 700+420+560=1680
a+2b+3c=3220
a+2b=1540
1540+3c=3220
3c=3220-1540
3c=1680
c=1680:3
c=560
a+b+560=1680
a+b=1680-560
a+b=1120
a+2b=1540 -
a+ b=1120
........................
b = 420
a+420=1120
a=1120-420
a=700
V: 700+420+560=1680