Question 401206: A dog was walking along a train track one day, and traveled along that track onto a train bridge. when the dog was 1/4 of the way across the bridge, he heard a train whistle from an oncoming train that was coming in the same direction the dog has already come. the dog bounded away from the train and made it to the end of the bridge at exactly the same time as the train. what the dog didnt know, but what was also true, was that the dog could have bounded toward the train and made it to the "start" of the bridge at exactly the same time as the train. the train was traveling at a speed of 30 miles/hour. how fast was the dog traveling
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! A dog was walking along a train track one day, and traveled along that track onto a train bridge. when the dog was 1/4 of the way across the bridge, he heard a train whistle from an oncoming train that was coming in the same direction the dog has already come. the dog bounded away from the train and made it to the end of the bridge at exactly the same time as the train. what the dog didnt know, but what was also true, was that the dog could have bounded toward the train and made it to the "start" of the bridge at exactly the same time as the train. the train was traveling at a speed of 30 miles/hour. how fast was the dog traveling.
:
This is thought problem that you can do in your head.
:
The dog has run 1/4 mile when the train enters the bridge
If the dog goes the same direction as the train is traveling, he will be
at the half way point on the bridge, when the train enters the bridge.
Therefore
The train travels the whole length of the bridge while the dog travels half the
length of the bridge.
therefore
The dog runs at half the speed of the train, or 15 mph
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