Car X began traveling at an average speed of 35 miles per hour. After 72 minutes, car Y began traveling at an average speed of 42 miles per hour. When both cars had traveled the same distance, both cars stopped. How many miles did car X travel from the time car Y began traveling until both cars stopped?	Choose the correct choice
A) 105	B) 140	C) 175	D) 210	E) 245
In 72 minutes, car X travels 42 miles.   Car Y gains 7 miles each hour, so it takes 6 hours to catch car X.   In 6 hours, car X travels 210 miles.   The answer is 210.
<result>D</result>
Car X began traveling at an average speed of 35 miles per hour. After 72 minutes, car Y began traveling at an average speed of 42 miles per hour. When both cars had traveled the same distance, both cars stopped. How many miles did car X travel from the time car Y began traveling until both cars stopped?