Răspuns :
a+b+c=680 Alfam nr c.
a+b =530 680-530=150
b+c=180 Alfam nr a.
------------------ 680-530=150
a=? b=? c=? Aflam nr b.
680-300=380
verificare:150+150+380=680
a+b =530 680-530=150
b+c=180 Alfam nr a.
------------------ 680-530=150
a=? b=? c=? Aflam nr b.
680-300=380
verificare:150+150+380=680
a+b+c=680 a+b=530 b+c=180 a+180=680 a=680-180 a=500 530+c=680 c=680-530 c=150 500+150+b=680 650+b=680 b=680-650 b=30 verific 500+30+150=680