Question 429220
  <pre><font face = "Tohoma" size = 4 color = "indigo"><b>
Hi
train is 40 miles per hour faster than the cars
Let x and (x+40mph)represent the speed of the car and train respectively
Question states*** Time is the same.  t = D/r
 {{{140/x = 280/(x+40)}}}    | Cross Multiplying 
  280x = 140(x+40)
  140x = 5600
     x = 40mph, the average speed of the car's.  train's average speed is 80mph

CHECKING our Answer*** 
 140mi/40mph = 280mi/80mph = 3.5 hr