Question

daca maresc de 3 ori suma pe care o am atuci voi avea cu 50 lei mai mult decat jumatate din suma initial.Cati lei am?

Answer 1

Notam:
s = suma initiala

Metoda algebrica :

3 × s = s : 2 + 50 |×2

6 × s = s + 100

6 × s - s = 100

5 × s = 100

s = 100 : 5

s = 20 lei

Metoda grafica:

3 × s /----/----/----/----/----/----/
s : 2 /----/

6 segmente egale - 1 segment egal = 5 segmente egale = 50

50 : 5 = 10 (valoarea unui segment egal)

3 × s = 6 × 10 = 60

s : 2 = 10

s = 10 × 2 = 20 lei

verificam:
3 × 20 = 20 : 2 + 50
60 = 10 + 50
60 = 60