f-faina
s-smanatana
u-unt
z-zahar
f+s+u+z=800
s=f-180⇒ f=s+180
s=z+40⇒ z=s-40
u=s/7 inlocuim in prima relatie
s+180+s+s/7+s-40=800
3s+s/7+140=800
(21s+s)/7=800-140
22s/7=660
s=(660·7)/22
s=210 g
f=s+180=210+180=390 g
z=s-40=210-40=170g
u=s/7=210/7=30g
deci
390+210+30+170=800 g