Bogdan= 40 lei + Adrian
Rada= 3 x Adrian
Bogdan= Rada + 20 lei
Bogdan= 40 lei + Adrian
Rada+ 20 lei= 40 lei + Adrian
3 x Adrian + 20lei=40 lei+ Adrian
2 x Adrian + 20 lei= 40 lei
2 x Adrian = 20 lei
Adrian = 10
Rada=3 x Adrian
Rada= 3 x 10 lei
Rada= 30 lei
Bogdan= Rada + 20 lei
Bogdan= 30 lei + 20 lei
Bogdan= 50 lei