Răspuns :
[tex]x=\,pretul\,initial\\
\Downarrow\\
x\cdot\frac{110}{100}\cdot\frac{90}{100}\cdot\frac{110}{100}=1089\\
\\
x=\frac{1089*100*100*100}{110*90*110}=1089000:1089=1000(lei)[/tex]
z*110/100 =1089 ; z =1089*100/110 =990
y*90/100 =990 ; y =990*100/90 =1100
x *110/100 =1100 ; x =1100*100/110 =1000 lei pret final
( 100+10% = 110% = majorarea pretului cu 10 % .....)
y*90/100 =990 ; y =990*100/90 =1100
x *110/100 =1100 ; x =1100*100/110 =1000 lei pret final
( 100+10% = 110% = majorarea pretului cu 10 % .....)