Răspuns :
x- lungimea drumului
x/3+1/4*(x-x/3)+18=x
x/3+2x/12+18=x
6x+12*18=12x
6x=12*18
x=36
1zi: 1 /3 *d (din drum) =>ramane 2 / 3 *d
2 zi: 1 /4 *2 / 3*d=1 / 6 *d=>ramane 2 /3 *d - 1 /6d=1 /2*d
3 zi:18km=>
1 /2 *d =18 => d =36km
2 zi: 1 /4 *2 / 3*d=1 / 6 *d=>ramane 2 /3 *d - 1 /6d=1 /2*d
3 zi:18km=>
1 /2 *d =18 => d =36km