5m stofa....5m catifea...315 lei /×2
10m stofa ...7 m catifea....525 lei
10m stofa.... 10 m catifea....630lei
10m stofa...7m catifea...525 lei
10m catifea-7m catifea=630lei-525lei
3m catifea=105lei
1m catifea=105:3=35 lei
525 lei =10m stofa+7m catifea
525lei=10m stofa +35×7lei
525lei=10m stofa +245lei
10m stofa=525 lei-245 lei
10m stofa= 280lei
1m stofa=280:10
1m stofa=28 lei