Explicație pas cu pas:
a+b+c=686
a+b=b+c+230
b=c+24
INLOCUIM
a+c+24+c=686
a+c+24=c+24+c+230
a+24=c+24+c+230-c
a+24=c+254
a-c=254-24
a-c=230
a=c+230
INLOCUIM
c+230+c+24+c=686
3c+254=686
3c=686-254
3c=432
c=432:3
c=144
a=c+230
a=144+230
a=374
b=c+24
b=144+24
b=168