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The shuttle service has a train going from Washington to NY City and from NY City to Washington every hour on the hour. The trip from one city to the other takes 4 1/2 hours, and all trains travel at the same speed. How many trains will you pass in going from Washington to NY City? Thanks for help.

 Dec 16, 2016

Best Answer 

 #1
avatar+37084 
+5

Let's say you are on the 10:00 train  ....  you will see the train coming form the opposite direction that was launched at 6:00 after you have been traveling approx 30 minutes ...

then t you will see the 7  8  9  10  launches as you travel for  4 1/2 hours  AND you will see the 11 12 13:00 and 14:00 train launches before you arrive at the launching station at 14:30  

That is a total of  9 trains going the opposit direction as you ....

 Dec 16, 2016
 #1
avatar+37084 
+5
Best Answer

Let's say you are on the 10:00 train  ....  you will see the train coming form the opposite direction that was launched at 6:00 after you have been traveling approx 30 minutes ...

then t you will see the 7  8  9  10  launches as you travel for  4 1/2 hours  AND you will see the 11 12 13:00 and 14:00 train launches before you arrive at the launching station at 14:30  

That is a total of  9 trains going the opposit direction as you ....

ElectricPavlov Dec 16, 2016
 #2
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+4

As our train leaves Washington, there is a train just 1 hour away from Washington, another 2 hours away...etc. Since the trains are traveling at the same rate of speed, we will pass the train that is 1 hour away from Washington in 1/2 hour, the train 2 hours away in 1 hour, or 1/2 hour after passing the preceding train. That is, we pass a train every 1/2 hour. Since the trip takes 4 1/2 hours or 9 half-hours, and as we leave Washington, we also pass a train just arriving. We, therefore, will pass a total of 10 trains during our trip!!.

 Dec 16, 2016
 #3
avatar+129840 
0

Suppose our train left the station at 12 midnight.  [every hour on the hour]....we  would meet no train at that time because the other train would have had to have left at 7:30AM the previuos evening....but this is impossible because it would not have left "on the hour"

 

Instead, 15 minutes later  [ at 12:15 AM].....we have met the train the left the other station at 8AM  the previous evening  [ and would arrive at our station of departure 15 minutes later....at 12:30 AM ]

 

Then......30 minutes later  [ at 12:45 AM]  we would meet the train that left at 9 AM the previous evening.......it has been traveling for 3 hrs, 45 min....and since we are 45 minutes from our station of departure......it's 45 min from its station of arrival......and it will arrive at 1:30 AM.....4 1/2 hours after its departure

 

Note the remaining patterns :

 

Our Time  → Time that the train we meet left the station of departure [our station of arrival ]

 

1:15 AM →  10 PM

1:45 AM → 11AM

2:15 AM → 12 AM

2:45 AM → 1 AM

3:15 AM → 2 AM

3:45 AM → 3 AM

4:15 AM → 4 AM 

 

Note that we don't meet any more trains after 4:15 AM.......we arrive at the station at 4:30AM, but the next train that departs that staion won't happen for 30 more minutes [ at 5 AM]

 

 

So....we pass a total of 9 trains......

 

 

 

cool cool cool

 Dec 17, 2016

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