A train 400 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
A) 298 m B) 279 m C) 500 m D) 289 m E) 900 m
Speed = 78 * 5/18 = 65/3 m/sec.   Time = 1 min = 60 sec.   Let the length of the train be x meters.   Then, (400 + x)/60 = 65/3   x = 900 m.   Answer: 900 m
<result>E</result>
A train 400 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?