A train 660 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?	Choose the correct choice from the following choices.
A) 640  B) 277  C) 500  D) 297  E) 435
Speed = 78 * 5/18 = 65/3 m/sec.   Time = 1 min = 60 sec.   Let the length of the train be x meters.   Then, (660 + x)/60 = 65/3   x = 640 m.   640nswer: 640
<result>A</result>
A train 660 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?