Distance Problem Solving

Question

A diesel train traveled north. 14 hours later a freight train left traveling at 70 mph in an effort to catch up to the diesel train. After traveling for six hours the freight train finally caught up. What was the diesel train's average speed?

Answer 1

The second freight train traveled for 6 hours at 70 miles per hour. This means that the freight train traveled 420 miles. Since it caught up with the first freight train, then that first train had to have also traveled 420 miles. However, the first freight train had traveled 420 miles over a period of 14 hours + 6 hours which is equal to 20 hours. Therefore, the average speed to the first freight train is 420 miles/20 hours which is equal to 21 miles per hour.