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A train traveling at 100 km an hour takes 3 seconds to enter a tunnel and an additional thirty seconds to pass completely through it. Find the length, in kilometers, of the train. Express your answer as a common fraction.

 Jan 28, 2021
 #1
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it takes three seconds for the length of the train to enter the tunnel

 

3 seconds is   3/3600 hr

 

3/3600 hr   * 100 km/hr =  1/12 km long train

 Jan 28, 2021
 #2
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A train traveling at 100 km an hour takes 3 seconds to enter a tunnel (T) and an additional thirty seconds to pass completely through it. Find the length (x), in kilometers, of the train. Express your answer as a common fraction.

 

Hello Guest!

 

\(t=\dfrac{s}{v}\)

\(3sek=\dfrac{T\cdot h}{100km}\cdot\dfrac{3600sek}{h}\\ T=\dfrac{3sek\cdot 100km}{3600sek}\)

\(T=0.08\overline{3}km\)

 

\(30sek=\dfrac{x\cdot h}{100km}\\ x=\dfrac{30sek\cdot 100km}{h}\cdot \dfrac{h}{3600sek}\\ \)

\(x=0.8\overline{33}km\)

 

The length of the train is \(\frac{5}{6}\ km=0.8\overline{33}\ km.\) 

laugh  !

 Jan 28, 2021

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