Trains A and B are traveling in the same direction on paralled tracks. Train A is traveling at 80 miles per hour and train B is traveling a 88 miles per hour. Train A passes a station at 9:20 P.M. If train B passes the same station at 9:35 P.M., at what time will train B catch up to train A?
Considering the train as a point and that the times quoted are in hour:minutes:
1--A's speed is 80mph
2--B's speed is 88mph.
3--In the 15 minutes it takes train B to pass the station after train A, train A travels d = 80(.25) = 20 miles.
4--From this point on, train B will be catching up with train A at the closing speed of 8mph.
5--Thus, train B will catch up with train A in t = 20/8 = 2.5 hours, or at 5:05.