SOLUTION: A train leaves a station and travels east at 72km/h. Three hours later, a second train leaves on a parallel track and travels east at 120km/h. How much time will it take until the

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: A train leaves a station and travels east at 72km/h. Three hours later, a second train leaves on a parallel track and travels east at 120km/h. How much time will it take until the       Log On


   

Question 953684: A train leaves a station and travels east at 72km/h. Three hours later, a second train leaves on a parallel track and travels east at 120km/h. How much time will it take until the second train catches up to the first train?
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
A train leaves a station and travels east at 72km/h. Three hours later, a second train leaves on a parallel track and travels east at 120km/h. How much time will it take until the second train catches up to the first train?
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let x=travel time of 2nd train
x+3=travel time of 1st train
distance=speed*travel time(same for both trains)
72(x+3)=120x
72x+216=120x
48x=216
x=4.5
How much time will it take until the second train catches up to the first train? 4.5 hrs