[tex]x=lungimea\ drumului\\
\frac{20x}{100}+\frac{30}{100}(x-\frac{20x}{100})+560=x\\
\frac{2x}{10}+\frac{3}{10}*\frac{80x}{100}+560=x\\
\frac{2x}{10}+\frac{24x}{100}+560=x\\
20x+24x+56000=100x\\
44x+56000=100x\\
56x=56000 \Rightarrow x=1000\ km\\
R:Drumul\ are\ 1000\ km.[/tex]