Răspuns :
a+b+c=130
a+b=70
----------------(-)
c=130-70
c=60
a=60:3
a=20
b=130-60-20
b=130-80
b=50
a+b=70
----------------(-)
c=130-70
c=60
a=60:3
a=20
b=130-60-20
b=130-80
b=50
Fie a, b si c cele 3 numere
a + b + c = 130
a + b = 70
a = c : 3
______________
130 - 70 = 60 ( c) → al treilea numar
a = 60 : 3 ⇒ a = 20 → primul numar
b = 70 - 20 = 50 → al doilea numar
Verific: 20 + 50 + 60 = 130 → suma celor 3 numere
a + b + c = 130
a + b = 70
a = c : 3
______________
130 - 70 = 60 ( c) → al treilea numar
a = 60 : 3 ⇒ a = 20 → primul numar
b = 70 - 20 = 50 → al doilea numar
Verific: 20 + 50 + 60 = 130 → suma celor 3 numere