2r+3c=21000, 3r+2c=24000, 3r=24000-2c, r=(24000-2c)/3, inlocuim pe r in prima relatie
2(24000-2c)/3+3c=21000, numitor comun 3
2(24000-2c)+3*3c=3*21000
48000-4c+9c=63000, 5c=63000-48000=15000, c=15000/5=3000 parale costa un colier
r=(24000-2*3000)/3=(24000-9000)/3=15000/3=5000 parale costa o rochie