x-traseul
x-[tex] \frac{4}{10} [/tex]·x=[tex] \frac{3x}{5} [/tex] traseul parcurs in prima zi
[tex] \frac{3x}{5}- \frac{2}{3} [/tex]·[tex] \frac{3x}{5} [/tex]=[tex] \frac{x}{5} [/tex] traseul a doua zi
[tex] \frac{x}{5} - \frac{2}{3} [/tex]·[tex] \frac{x}{5} = \frac{x}{15} [/tex] a treia zi
[tex] \frac{x}{15} =10=>x=150 km in cele 4 zile