A train 600 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?	Select.
A) 277 m  B) 700m  C) 500 m  D) 187 m  E) 1678 m
Speed = 78 * 5/18 = 65/3 m/sec.   Time = 1 min = 60 sec.   Let the length of the train be x meters.   Then, (600 + x)/60 = 65/3   x = 700 m.   Answer:700m
<result>B</result>
A train 600 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?