Soarer's solution is the only one provided

Let the speed of the leader be a mile/s
the speed of the officer be b mile/s
Time the officer needs to go to the back of the parade:

therefore the total distance he walked is
Time the leader needs to go to the distant point:

Since they arrived at the same time,



2ab = b²-a²
a²+2ab-b² = 0
Solve it by quadratic formula,
since a,b are positive,
a = (-1+)b
a+b = b

Total distance the offer walked is
=
= +1 miles.