Two trains start simultaneously from opposite ends of a 150-km route and travel toward each other on parallel tracks. Train X, traveling at a constant rate, completes the 150-km trip in 4 hours. Train Y, travelling at a constant rate, completes the 150-km trip in 3.5 hours. How many kilometers had Train X traveled when it met Train Y?	Choose the correct choice from the following options.
A) 68
B) 70
C) 72
D) 74
E) 76

Rationale: if the two trains cover a total distance d , then train x travels ( 7 / 15 ) * d while train y travels ( 8 / 15 ) * d . if the trains travel 150 km to the meeting point , then train x travels ( 7 / 15 ) * 150 = 70 km . the answer is b .
Answer: B