irina,radu si marius au anpreuna750de timbre.irina are cu 30de timbre mai multe decat radu ,iar marius de 4 orimai multedecat radu.Cate timbre are fiecare.
notam irina a. radu b marius c a+b+c=750 a=b+30 c=4xb facem segmente a|____|+30 b|____| c|____|____|____|____| egalam 750-30=720 cate timbre are radu ? 720:6=120 este b adica timbre are radu cate timbre are irina? 120+30=150 cate timbre are marius? 120x4=480 proba 120+150+480= 270+480=750
