Question

A train 800 metres long is running at a speed of 78 km/hr. If it crosses a tunnel in 1 minute, then the length of the tunnel (in meters) is:

• A. 130
• B. 360
• C. 500
• D. 540

Answer 1

Answer: (C)

500

$Speed=(78\times \frac{5}{18})m/sec=\left(\frac{65}{3}\right)m/sec$
Time = 1 minute = 60 seconds.
Let the length of the tunnel be x metres.
Then, $\left(\frac{800+x}{60}\right)=\frac{65}{3}$
$\Rightarrow 3(800+x)=3900$
$\Rightarrow x=500$