A train 900 m long is running at a speed of 78 km/hr. If it crosses a tunnel in 1 min, then the length of the tunnel is?  Pick one
A) 400  B) 540  C) 500  D) 520  E) 589
Speed = 78 * 5/18 = 65/3 m/sec.   Time = 1 min = 60 sec.   Let the length of the train be x meters.   Then, (900 + x)/60 = 65/3   x = 400 m.   400nswer: Option 400
<result>A</result>
A train 900 m long is running at a speed of 78 km/hr. If it crosses a tunnel in 1 min, then the length of the tunnel is?