x=lungimea parcursului, (x/3)+10, prima zi, x-(x/3)-10=(2x/3)-10 km ramasi dupa prima zi
[(2x/3)-10]/2+10=(2x/6)-5+10=(x/3)+5, a doua zi, (2x/3)-10-(x/3)-5=(x/3)-15 km ramasi dupa a doua zi
[(x/3)-15]/2+50=(x/6)-15/2+50 a treia zi, x=(x/3)+10+(x/3)+5+(x/6)-(15/2)+50, numitor comun 6,
6x=2x+60+2x+30+x-45+300, x=345km