A train 880 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 most appropriate option.
A) 510
B) 540
C) 500
D) 420
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, (880 + x)/60 = 65/3   x = 420 m.   Answer: Option 420
<result>D</result>
A train 880 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?