Răspuns :
a-suma economisita de mama
b-suma economisita de tata
c-suma economisita de bunica
a+b+c=923lei
b=a-120
a+80=c
a+(a-120)+a+80=923⇒3a+80-120=923⇒3a+80=923+120=1043⇒3a=1043-80=963⇒a=963.3=321lei
b=321-120=201lei
c=321+80=401lei
b-suma economisita de tata
c-suma economisita de bunica
a+b+c=923lei
b=a-120
a+80=c
a+(a-120)+a+80=923⇒3a+80-120=923⇒3a+80=923+120=1043⇒3a=1043-80=963⇒a=963.3=321lei
b=321-120=201lei
c=321+80=401lei
m + t + b = 923
m - 120 = t
m + 80 = b
120 + 80 = 200
923 - 200 = 723
723 : 3 = 241 lei are tata
241+ 120 = 361 lei are mama
241 + 80 = 321 lei are bunica
m - 120 = t
m + 80 = b
120 + 80 = 200
923 - 200 = 723
723 : 3 = 241 lei are tata
241+ 120 = 361 lei are mama
241 + 80 = 321 lei are bunica