Răspuns:
|_|_|_|_|_|_|_|_|_|_| lungimea totala a drumului (10 parti)
|_|_|_| 3/10 prima zi (a)
|_|_|_|_|_|_|_| restul R1(7/10)
|_|_| 2/7 a doua zi (b)
|_|_|_|_|_| R2 (5/10) rest2
|_|_|_| 3/5 a treia zi c
|_|_| 20 km (2/5)
20:2= 10 km (o parte )
c= 10*3=30 km (a treia zi)
R2= 20+30=50 km (5/10)
t= 2*R2= 2*50= 100 km lungimea drumului
a= 3/10 = 3*100/10= 300/10= 30 km prima zi
R1= 100-30= 70 km
b= 2/7 *R1= 2*70/7= 140 /7= 20 km (a doua zi)
Verif: 30+20+30+20 = 100 km