Nota cu x - distanta pe care o are de parcurs
prima zi: 35%x = 35/100x = 7/20x
a doua zi: 80%(x-7/20x) = 80/100*13/20x = 13/25x
a treia zi 260 km
x = 7/20x + 13/25x +260 (aducem la acelasi numitor comun)
100x = 35x + 52x +26000
13x = 26000
x = 2000 km
