Fie d, distanta parcursa in ziua a 2-a. Atunci avem:
zi1: d-70
zi2: d
zi3: d+20 si le adunam:
3d-50 = 1300
3d=1350
d=1350:3=450 km in ziua a 2-a
zi1: 450-70 = 380 km
zi3: 450+20=470 km
----------------------------
Verificare: zi1+zi2+zi3=380+450+470=1300 km, corect