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# A train that is 1km lone is moving along a straight track toward a tunnel that is 1km long. If the train travels at 100 km/h, then the number of minutes that

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A train that is 1km lone is moving along a straight track toward a tunnel that is 1km long. If the train travels at 100 km/h, then the number of minutes that the train takes to go through the tunnel is

Guest Mar 13, 2017

### Best Answer

#2
+84066
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Another approach is to just see how long it will take the back of the train to clear the tunnel once the front of the train arrives at the tunnel entrance

100km / hr  =  100/3600(km/sec)  = 1/36km/sec

And the back of the train must travel 2km to completely clear the tunnel.....so....

D / R  = T

2km / (1/36km/sec)  =  (2)/ (1/36) sec  =  (2 * 36)sec  = 72 sec

CPhill  Mar 13, 2017
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### 2+0 Answers

#1
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100 /60 = 1 2/3 km/minute - the speed of the train.

1 / (1 2/3) =0.6 minutes or 36 seconds for the front-end of the train to emerge from the tunnel.

0.6 x 2 =1.2 minutes or 72 seconds - for the back-end of the train to emerge from the tunnel.

Guest Mar 13, 2017
#2
+84066
+5
Best Answer

Another approach is to just see how long it will take the back of the train to clear the tunnel once the front of the train arrives at the tunnel entrance

100km / hr  =  100/3600(km/sec)  = 1/36km/sec

And the back of the train must travel 2km to completely clear the tunnel.....so....

D / R  = T

2km / (1/36km/sec)  =  (2)/ (1/36) sec  =  (2 * 36)sec  = 72 sec

CPhill  Mar 13, 2017

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