1)2x/7 ; x-25/7 =7x/7-2x/7 =5x/7 rest
2)1/4 *5x/7 =5x/28 ; 5x/7-5x/28 =20x/28-5x/28 =15x /28 rest
3)2/5 *15x/25 =3x/14 ; 15x/20 -3x/14 =15x/28-6x/28 =9x/28 rest
4)5/9 *9x/28 =5x/28
5) 6 lei
2x/7+5x/28+3x/14+5x/28 +6 = x numitor 28
8x+5x+6x+5x+168 =28x
28x-8x-5x+6x+5x =168
4x =168
x = 42 km