Răspuns :
20(km-o ora) + 20(km-o ora) + 10 (km-jumatate de ora)= 50 de km total
20km*2=40km(in 2 ore)
20km/2=10km(in 30 min)
40km+10km=50km(in 2 ore si 30 de min)
20km/2=10km(in 30 min)
40km+10km=50km(in 2 ore si 30 de min)