a:4+b:2+c:3= 120 /×12
3a+6b+4c= 1440
b:2=a:4+24
b:2= 4×c:3
egalam cele doua relatii
a:4+24= 4×c:3 /×12
3a+288= 16 c ==> a = (16c-288):3
b:2=4×c:3 /×6
3b=8c ==> b= 8c:3
inlocuim in a doua relatie in functie de c
16c-288+16c+4c= 1440
36c = 1440+288
36c = 1728
c = 1728:36
c = 48
b = 8×48:3 = 384:3 = 128
a = (16×48-288):3 = (768-288):3 = 480:3 = 160
a = 160
b = 128
c = 48
160+128+48 = 336 (suma)