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A 250 m train travels through a 2km tunnel at 27 km/hr. How long is it from the time the front of the train enters the tunnel, to when it completely leaves it?

Apr 12, 2020

#1
+127
0

the train takes let's start by converting everything to the same unit. In this case, I will convert everything into meters. 2km = 2000m, and 27 km/h is 27000m. lets now convert the train to a point. in order to this, we take off all the train carts. The bridge is now 500(add the length to the beginning and the end because when the front of the train touches the bridge, there is still 250m of train cars behind it, and when the front of the train reaches the end of the bridge, there is still 250 meters of the train behind it. If this doesn't convince you, draw yourself a picture)m longer. the 'bridge' is now 2500 meters long. if every minute the train travels 2700/60 = 45 meters, in 2500/45 = 55 1/2 = 55 min and 30seconds, the train will clear the bridge.

Apr 12, 2020
#2
+28025
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The train will have to cover  2 km + 250 m to completely clear the tunnel

2.25 km  /  27 km/hr  = .083333 hr   =   300 seconds

Apr 12, 2020