The second person is walking faster than the first person.
Solution:
Given, One person walks 
 miles in each
 miles in each 
 hour.
 hour. 
Another person walks 
 miles in each
 miles in each 
 hour.
 hour. 
We have to find who is walking faster? 
Now, we know that, distance = speed x time
Let us find the speed of each person 
Speed of first person:

Speed of second person:

We know that, 

Hence, the second person is walking faster than the first person.