SOLUTION: I am travelling at 100 kmh I catch up to a train that is travelling at 80kmh. The train is 500 meters long. How long does it take me to pass this train. How far do I travel before

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Question 270267: I am travelling at 100 kmh I catch up to a train that is travelling at 80kmh. The train is 500 meters long. How long does it take me to pass this train. How far do I travel before I pass the train
Pete
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
This is a problem of relative speeds
with 2 trains moving at constant speed
The problem doesn't change at all if
I say that the train I am trying to pass
is standing still and I m moving at the
difference in our speeds, 100+-+80+=+20 km/hr
Now, with the slower train stopped, how long
does it take my front end to go from it's
back end to it's front end, or 500m
d+=+r%2At
t+=+d%2Fr
t+=+500%2F20000 (I converted km/hr to m/hr)
t+=+5%2F200
t+=+1%2F40 hr
t+=+%281%2F40%29%2A60 min
t+=+1.5 min
I passed the 500 m long train at my actual speed of 100000 m/hr, so
d+=+100000%2A%281%2F40%29
d+=+10000%2F4
d+=+2500m or
d+=+2.5km actual ground covered