Răspuns:
Explicație pas cu pas:
D = drumul
Prima zi 2D/5
A doua zi 2D/5*2/3 = 4D/15
Primele doua zile 2D/5 + 4D/15 = 6D/15 + 4D/15 = 10D/15 = 2D/3
A treia zi D - 2D/3 = D/3 = 40 km
D = 40*3 = 120 km
Prima zi 2*120/5 = 48 km
A doua zi 4*120/15 = 32 km