Two trains start simultaneously from opposite ends of a 140-km route and travel toward each other on parallel tracks. Train X, traveling at a constant rate, completes the 140-km trip in 4 hours. Train Y, travelling at a constant rate, completes the 140-km trip in 3 hours. How many kilometers had Train X traveled when it met Train Y?	Choose the correct choice from the following choices.
A) 60 B) 64 C) 68 D) 72 E) 76
If the two trains cover a total distance D, then Train X travels (3/7)*D while Train Y travels (4/7)*D. If the trains travel 140 km to the meeting point, then Train X travels  (3/7)*140= 
<gadget id="calculator"> (3/7)*140</gadget>
<output>60</output>
60 km.   The answer is 60.
<result>A</result>
Two trains start simultaneously from opposite ends of a 140-km route and travel toward each other on parallel tracks. Train X, traveling at a constant rate, completes the 140-km trip in 4 hours. Train Y, travelling at a constant rate, completes the 140-km trip in 3 hours. How many kilometers had Train X traveled when it met Train Y?