The train

The train passed the observer in the 20s and passed through a 1500m tunnel in 2 minutes. Calculate the speed (km/h) and train length.

Correct result:

v =  54 km/h
l =  300 m

Solution:

v• (20/3600) = s
1500/1000 + s = v•2/60

3600s-20v = 0
3000s-100v = -4500

s = 3/10 = 0.3
v = 54

Our linear equations calculator calculates it.

$l=s\cdot 1000=0.3\cdot 1000=300\text{ m}$

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