Răspuns:
Fie x suma Elenei
Irina are 2/3 x
Calin are 2/4 *2/3 x
X+2/3x +2/4*2/3 x=120
x+2x/3+4/12 x=120
x+2x/3+x/3=120
3x+2x+x=360
6x=360=>x=60 lei are Elena
Irina are 2/3 x= 2*60/3=120/3=40 lei
Calin are 2/4*40=80/4=20 lei
Verificare =60+40+20=120 lei
Explicație pas cu pas:
Spor la scris! Sper ca te-am ajutat!