x = pret initial
[tex] x + \frac{20}{100}x + x + \frac{10}{100}(x+\frac{20}{100}x) = 264
[/tex]
[tex] 2x + \frac{20x}{100} + \frac{10x}{100}+\frac{200x}{10000} = 264 [/tex]
[tex] 2x + \frac{2x}{10} + \frac{x}{10}+\frac{2x}{100} = 264 [/tex]
[tex]\frac{200x}{100}+\frac{20x}{100}+\frac{10x}{100}+\frac{2x}{100}=26400/100[/tex] |· 100
[tex]200x+20x+10x+2x=26400[/tex]
[tex]232x=26400[/tex] | : 4
[tex]58x=6600[/tex] | : 2
[tex]29x=3300[/tex]
[tex]x=\frac{3300}{29}[/tex]
