SOLUTION: Trains A and B are traveling in the same direction on parallel lines. Train A is traveling at 40 miles per hour and Train B is traveling 50 miles an hour. Than Train A passes a st

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Question 148282: Trains A and B are traveling in the same direction on parallel lines. Train A is traveling at 40 miles per hour and Train B is traveling 50 miles an hour. Than Train A passes a station at 12:25 PM. If Train B passes the same station at 12:35 PM. What time will B catch up with Train A? When will Train B catch up with Train A?
When will Train B catch up to Train A?
Time ??? PM or AM?
Thanks

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Imagine that I am a passenger on train B. I have a stopwatch and a very
accurate clock too. I've got a cell phone and I'm in contact with
someone at the station
I know the seed of train A and train B also.
I tell the station "Let me know exactly when train A passes the station"
They tell me "Train A just passed"
My clock tells me it's 12:25
Then my train, train B, passes the station.
My clock says it's 12:35. I start my stopwatch
10 minutes have passed, or 10%2F60of an hour and since d+=+r%2At
d+=+40%2A%2810%2F60%29
d+=+40%2F6mi
That's how far train A is from the station when I go past the station.
I know train A is 40%2F6 mi ahead of me, but when I stop the
stopwatch we will be side by side.
Let t = time from start to stop
d = the distance I have to go to meet train A
d+-+40%2F6 is the distance train A has to go to meet me
For A:
d+-+%2840%2F6%29+=+40t
For B:
d+=+50t
Substitute the 2nd equation into the 1st
50t+-+%2840%2F6%29+=+40t
multiply both sides by 6
300t+-+40+=+240t
60t+=+40
t+=+40%2F60 hr or 40 min
If I started my stopwatch at 12:35 PM, then the trains meet
at 1:15 PM answer
check answer:
d+=+50t
d+=+50%2A%2840%2F60%29
d+=+100%2F3 mi
Train A covers this distance (station to meeting) in
10%2F60+%2B+40%2F60+=+50%2F60 hr
d%5BA%5D+=+r%5BA%5D%2At
100%2F3+=+40%2A%2850%2F60%29
100+=+120%2A%285%2F6%29
600+=+120%2A5
600+=+600
OK