Question 817856
  Let's call them Train A and Train B.
   Let Train A be the one that travels 85 mph,     Train  B travels 65 mph
   They are 180 miles apart.
  We do not know how far each one travels when they meet, so 
 Let d  = distance Train A travels  and then 180 - d will  equal the distance Train B travels.
    Train A.             Train B
      d   = rt.             d = rt
      d = 85t.            180 -d =  65t
    Solve for t.           Solve for t
  t =  d/85.               t = (180 - d)/65
   Set the 2 expressions for t equal to each other.
    d/85 = (180-d)/65
   Solve for d.
    d= 102 miles 
to find t, train A. ;  d = 85t
  102 = 85t,   t =. 1.2 hrs.
For Train B , distance = 180 - 102 = 78 miles.
       So 78 = 65t
      Solving for t also gives us t = 1.2 hours