a+b+c+d= 2851
a+b=1000
d= c+285
d= b+570
1000+c+c+285=2851
1000+2c+285=2851
2c+1285=2851 2c=1566 c=783 elevi a treia scoala
d=783+285 d=1068 a patra scoala
1068=b+570 b=1068-570 b=498 elevi a doua scoala
a+498=1000 a=1000-498 a=502 prima scoala
proba: 502+498+783+1068=1000+1851=2851