Răspuns:
x-lungimea drumului
1 zi: x/7
x - x/7 = 6x/7 restul dupa prima zi
2 zi: 2/3 x 6x/7 = 12x/21 = 4x/7
6x/7 - 4x/7 = 2x/7 noul rest
3 zi: 3/8 x 2x/7 = 6x/56 = 3x/28
x= x/7 + 4x/7 + 3x/28 + 40
28x = 4x + 16x + 3x + 40*28
28x = 23x + 40 * 28
28x - 23x = 40*28
5x = 1120
x = 224 km
1 zi: 32 km
2 zi: 128 km
3 zi : 24 km