Răspuns:
a |___|___|___|___|
prima zi:
1/4 (1 segment)
b |___|___|___|
a doua zi
1/3 (1 segment)
c |___|___|
a treia zi:
1/2 (1 segment = 30 km)
30km = a treia zi
30km = a doua zi
30km = prima zi
30×4=120 km de parcurs
Metoda folosita se numeste "Metoda mersului invers".