x- traseu
1 zi: x-25x/100= A - rest
2 zi: A-40A/100=B - noul rest dupa a doua zi
3 zi: B-60B/100=C - rest dupa a patra zi
4 zi: c=405
B-60B/100=405
B-6B/10=405 - amplif cu 10
10B-6B=4050
4B=4050
B=1012,5 km
A-40A/100=1012,5
A-4A/10=1012.5 - amplif cu 10
10A-4A=10125
6A=10125
A=1687.5 km
x-25x/100= 1687.5
x-x/4=1687.5 Amplif cu 4
4X-X=6750
3x=3750
x=2250