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Question 173780: Trains A and B are traveling in the same direction on parallel tracks. Train A is traveling at 100mph and train B is traveling at 120mph. Train A passes a station at 8:15A.M. If train B passes the same station at 8:30A.M., what time will train B catch up to train A?
I don't even know if I am asking this question in the right section or not, but it has me baffled.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Trains A and B are traveling in the same direction on parallel tracks. Train A is traveling at 100mph and train B is traveling at 120mph. Train A passes a station at 8:15A.M. If train B passes the same station at 8:30A.M., what time will train B catch up to train A?
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Train A DATA:
rate = 100 mph ; distance = x miles ; time = d/r = x/100 hrs
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Train B DATA:
rate = 120 mph ; distance = x miles ; time = d/r = x/120 hrs
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EQUATION:
time A - time B = (1/4) hr
x/100 - x/120 = 1/4
Multiply thru by 4 to get:
x/25 - x/30 = 1
30x - 25x = 25*30
5x = 25*30
x = 5*30 = 150 miles
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Train A time = x/100 = 150/100 = 3/2 hr
8:15 + (3/2) hr = 9:45 A.M.
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