A person walks at a rate of 3mph to a destination.  The person walks at a rate of 5mph on the return trip.  The round trip takes 1 hour.  We are to find the distance walked.

=>  let time walked at 3mph = t

=>  let time walked at 5mph = 1 - t

=>  We choose to solve for t (the time walked at 3mph) using the distance formula.  We know that the distance on the first part of the trip is equal to the distance of the return trip.

=> d = rt

=. distance walked at 3mph = distance walked at 5 mph

=> 3t = 5( 1 - t)

=> 3t = 5 - 5t

=> 8t = 5

=> t = 5/8 hour

We now substitute  5/8 hour for t into the distance formula.

=> d = rt

=> d = 3(5/8)

=> d = 1 7/8 miles

The walked on each part of the trip was 1 7/8 miles.

The total distance walked to and from was 3 3/4 miles.