Question 470368
Trains A and B are traveling in the same direction on parallel tracks. Train A is traveling at 60 miles per hour and train B is traveling at 80 milers per hour. Train A passes a stations at 12:20 p.m. if train B passes the same station at 12:35 p.m. at what time will train B catch up to train A?
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Train A has a 15 minute head start.  Traveling at 60 mph, the head start distance is 60*1/4 = 15 miles
The RELATIVE speed of the two trains is 80 - 60 = 20 mph
At this relative speed the time needed for train B to make up the 15 mile head start is:
t = 15 mi/ 20 mph = 3/4 hr = 45 mins.

Therefore, the time when train B will catch train A is: 12:35pm + 45 mins = 1:20 pm