Trains A and B are traveling in the same direction on parallel tracks. Train A is traveling at 100 mile per hour and train B is traveling at 125 mile per hour. Train A passes a station at 3:15pm. If train B passes the same station at 3:27 pm at what time will train B catch up with train A?

Question

Trains A and B are traveling in the same direction on parallel tracks.  Train A is traveling at 100 mile per hour and train B is traveling at 125 mile per hour.  Train A passes a station at 3:15pm.  If train B passes the same station at 3:27 pm at what time will train B catch up with train A?

bobpursley · Answer

They are 12 min apart (1/5 hr). relative velocity=25mi/hr time: 1/5 hr at start distance apart=100*1/5=20miles at start timeto catchup= 20miles/25mi/hr= 4/5 hr