Question

Dupa o scumpire cu 20% un obiect costa 24 lei. Cat costa inainte?

Answer 1

$\frac{20}{100} x+x=24 \\ 120x=2400 \\ x=2400:120=20 lei$

Answer 2

[100+20]/100 ·y=24lei;
⇒120/100 ·y=24lei;
⇒y=24/120/100
⇒y=24·100/120
⇒y=24·10/12
⇒y=2·10
⇒y=20[lei-costa inainte];