a- lungimea drumului
In prima zi se parcurge :
25\% \times a = \frac{25}{100} \times a = \frac{1}{4} \times a = \frac{a}{4}
Restul din drum dupa prima zi :
a - \frac{a}{4} = \frac{4 \times a - a}{4} = \frac{3 \times a}{4}
In a doua zi se parcurge :
\frac{1}{3} \times \frac{3 \times a}{4} = \frac{a}{4}
In a treia zi se parcurg 12 km
In total se parcurge :
a = \frac{a}{4} + \frac{a}{4} + 12 = \\ \\ 4 \times a = 2 \times a + 48 \\ \\ 2 \times a = 48 \\ \\ a = 24 \: km
