Car X began traveling at an average speed of 35 miles per hour. After 36 minutes, car Y began traveling at an average speed of 38 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 from the following choices.
A) 105 B) 140 C) 175 D) 210 E) 245

Rationale: "in 36 minutes , car x travels 21 miles . car y gains 3 miles each hour , so it takes 7 hours to catch car x . in 7 hours , car x travels 245 miles . the answer is e ."
Answer: E