Răspuns :
facem problema de la coada la cap
100-50+150-70+65-120=75 lei a avut Andrei
proba
75+120-65+70-150+50=100lei
100-50+150-70+65-120=75 lei a avut Andrei
proba
75+120-65+70-150+50=100lei
a+120-65+70-150+50=100
a+120=100+65-70+150-50=195
a=195-120=75
a+120=100+65-70+150-50=195
a=195-120=75