traseu=x
Prima zi
[tex]\frac{40}{100}\times x[/tex]
Rest: [tex]x-\frac{40x}{100} =\frac{60x}{100}[/tex]
A doua zi
[tex]\frac{35}{100}\times\frac{60x}{100} =\frac{21x}{100}[/tex]
A treia zi 156 km
[tex]\frac{40x}{100}+\frac{21x}{100}+156=x[/tex]
61x+15600=100x
39x=15600
x=400 km