[tex]x - lungimea \: traseului[/tex]
[tex] \frac{3}{10} \times x = \frac{3x}{10} \: (prima \: zi)[/tex]
[tex]x - \frac{3x}{10} = \frac{10x}{10} - \frac{3x}{10} = \frac{10x - 3x}{10} = \frac{7x}{10} \: (rest)[/tex]
[tex] \frac{1}{4} \times \frac{7x}{10} = \frac{1 \times 7x}{4 \times 10} = \frac{7x}{40} \: (a \: doua \: zi)[/tex]
[tex] \frac{3x}{10} + \frac{7x}{40} + 168 = x \: | \times 40[/tex]
[tex]12x + 7x + 6720 = 40x[/tex]
[tex]12x + 7x - 40x = - 6720[/tex]
[tex] - 21x = - 6720 \: | \div ( - 21)[/tex]
[tex]x = 320 [/tex]
