Question 932788: Two people were crossing a bridge together and were 3/8 across the bridge when they saw a train approaching the bridge from behind. One person ran toward the train and reached the entrance of the bridge at the exact moment of time that the train did. The other person ran away from the train at the same speed as the first person and reached the end of the bridge at the exact moment of time the train did. At what speed did the people run, given that the train was moving at a speed 80km/h?
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! Two people were crossing a bridge together and were 3/8 across the bridge when they saw a train approaching the bridge from behind.
One person ran toward the train and reached the entrance of the bridge at the exact moment of time that the train did.
The other person ran away from the train at the same speed as the first person and reached the end of the bridge at the exact moment of time the train did.
At what speed did the people run, given that the train was moving at a speed 80km/h?
:
Assuming both men run at the same speed
The one running towards the train and arrives at the same time as the train, has run 3/8 of the bridge.
Meanwhile, the other man will have run 3/8 in the opposite direction, so he is now 6/8 from the train end of the bridge, just as the train enters bridge.
Therefore he runs the remaining 2/8 while the train covers whole length of the bridge.
His speed then: 2/8 * 80 = 20 km/hr is the running speed of the two men
:
Did this make sense to you?
|
|
|
