Question 182486: a passenger train leaves a train depot 2 h after a frieght train leaves the same depot. the frieght train is traveling 20 mph slower than the passenger train. find the rate of each train if the passenger train overtakes the freight train in 3 h
Answer by tvandenberg(45)   (Show Source):
You can put this solution on YOUR website! Since, distance = speed * time, and we know that the distances are equal, we can say,
Speed(P)*time(P)=Speed(F)*time(F)
From your givens, we know that:
time(P) = 1 hr (3 hr - 2 hr)
time(F) = 3 hr
We also know that,
Speed(P) = Speed(F) + 20
So, back to the first equation, we can now say:
[Speed(F)+20]=[Speed(F)]
I will use the notation F and P for speeds.
F+20=3F ... 2F = 20... F = 10
P = F + 20 = 10 + 20 = 30
Speed of passenger train = 30 mph, freight train = 10 mph
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