Prima zi
[tex] \frac{1}{5}x[/tex]
A doua zi
[tex] \frac{1}{5} x + 24[/tex]
A treia zi
[tex] \frac{1}{2} x[/tex]
[tex] \frac{1}{5} x + \frac{1}{5} x + 24 + \frac{1}{2}x = x[/tex]
[tex] \frac{2}{5} x + 24 + \frac{1}{2} x = x[/tex]
[tex]4x + 240 + 5x = x[/tex]
[tex]9x - x = 240[/tex]
[tex]8x = 240[/tex]
[tex]x = 30km[/tex]
in a treia zi el a parcurs
[tex] \frac{1}{2} x = 30 \div 2 = 15km[/tex]
