Question

Daca as avea de patru ori mai putine timbre decat am, as avea cu 120 mai putine decat am. Calculati cate timbre are.

Answer 1

x:4=x-120     x-numarul timbrelor
x=4x-480
480=4x-x
480=3x⇒x=480:3
              x=160

Answer 2

a-3a/4=a-120
4a/4-3a/4=a-120
a/4=a-120
⇒a=120+a/4
⇒120=a-a/4
⇒120=4a/4-a/4
⇒120=3a/4
⇒a=4·120/3
⇒a=4·40
⇒a=160;