Train A leaves the station traveling at 30 miles per hour. Two hours later train В leaves the same station traveling in the same direction at 42 miles per hour. How many miles from the station was train A overtaken by train B? Choose one.
A) 150	B) 170	C) 190	D) 210	E) 230

Rationale: "after two hours , train a is ahead by 60 miles . train b can catch up at a rate of 12 miles per hour . the time to catch up is 60 / 12 = 5 hours . in 5 hours , train a travels another 30 * 5 = 150 miles for a total of 210 miles . the answer is d ."
Answer: D