Răspuns:
1) 35x/100 =7x/20 ; x-7x/20 =13x/20 rest
2) 40/100 *13x/20 =13x/50 ; 13x/20-13x/50 =65x/100-26x/100 =39x/100
3) 50/100 *39x/100 =39x/200 ;
4) 117 km
7x/20 + 13x/50 + 39x/200 + 117 =x numitor 200
70x+52x+39x+23400 =200x
200x-70x-52x-39x =23400
39x=23400
x =600 km
Explicație pas cu pas: