Question

Salariul unui angajat se micsoreaza cu 20%.Dupa un timp salariul se mareste cu 20% si astfel acesta devine 1440 lei.Calculati cat a fost salariul initial.?

Answer 1

100-20/100 ·x=y ⇒80/100·x=y
⇒100+20/100·y=1440[lei] ⇒120/100·y=1440[lei];
⇒120/100·y=1440[lei]
⇒y=1440/120/100
⇒y=1440·100/120
⇒y=1440·10/12
⇒y=1440·5/6
⇒y=240·5⇒y=1200;
⇒80/100·x=1200[lei]
⇒x=1200/80/100
⇒x=1200·100/80
⇒x=1200·10/8
⇒x=1200·5/4
⇒x=300·5⇒x=1500[lei-salariul initial];