Question

In urma unor reduceri de craciun pretul unui televizor se reduce cu 25% . Dupa sarbatori noul pret se mareste cu 20% ajungand sa coste 3600 lei. Aflati
pretul initial al televizorului.

Answer 1

$x\to pretul \ initial \\\\ 25\% \ din \ x=\frac{\not25}{\not100}*x= \frac{1}{4}*x\to\frac{x}{4}-reducerea \\\\ x^{(4}-\frac{x}{4}= \frac{4x-x}{4}\to\frac{3x}{4}-noul \ pret \\\\ 20\% \ din \ \frac{3x}{4}=\frac{\not20}{\not100}*\frac{3x}{20}=\frac{1}{5}*\frac{3x}{20}\to\frac{3x}{100}-marirea \\\\ \frac{3x}{4}^{(25}+\frac{3x}{100}= \frac{75x+3x}{100}\to \frac{78x}{100}-noul \ nou \ pret \\\\ \frac{78x}{100}=3600 \\\\ x=\frac{100*3600}{78} \\\\ x=100*46,153 \\\\ \boxed{x=4615,3}$