PERSON            SPEED           TIME        DISTANCE
Austin                             4              d
Snelling                           5              d
Difference         1 

Let d be the one way distance, in miles.

Then the rate by Austin   was    miles per hour,

     the rate by Snelling was    miles per hours.


We are given that Austin traveled 1 mph faster than Snelling,
so we can write this equation

     -  = 1  mph.


At this point, the setup is complete.
To solve this equation, multiply both sides by 4*5 = 20, which is the common denominator.

You will get then

    5d - 4d = 20,

       d    = 20.


So, one way distance is 20 miles.    ANSWER

Austin made the hike to Mt. St. Helen's in 4 hours, and Snelling made the
same hike in 5 hours. How far was the hike if Austin hiked 1 mph faster than
Snelling?

All algebra books tell you make DRT tables for DRT problems:

          distance = rate * time
Austin   |    x    |  r+1 |  4
Snelling |    x    |   r  |  5








x = 5r = 5(4) = 20 miles

Edwin