Afreight train leaves the train station 4hrs before a passenger train. the two trains are traveling in the same direction on parallel tracks. if the rate of the passenger train is 11 mph faster than the freight train, how fast is each train traveling if the passenger train passes the freight train in 20hrs?

Let the speed of the freight train be x mph.
Then the speed of the passenger train is (x + 11) mph.
Distance traveled by the freight train in 20 hours = 20x miles.
The passenger train has 20 - 4 = 16 hours to pass the freight train after traveling 20x miles at (x + 11) mph.


16x + 176 = 20x
4x = 176
x = 44
The speed of the freight train is 44 mph and the speed of the passenger train is 55 mph.