Car X began traveling at an average speed of 35 miles per hour. After 84 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) 140 B) 175 C) 210 D) 245 E) 270
In 84 minutes, car X travels 49 miles.   Car Y gains 7 miles each hour, so it takes 7 hours to catch car X.   In 7 hours, car X travels 245 miles.   The answer is 245.
<result>D</result>
Car X began traveling at an average speed of 35 miles per hour. After 84 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?