A train covers a distance of 18 km in 3 min. If it takes 4 sec to pass a telegraph post, then the length of the train is?
Pick one:  A) 370  B) 380  C) 390  D) 400  E) 410
Speed = (18/3 * 60) km/hr = (360 * 5/18) m/sec = 100 m/sec.   Length of the train = 100 * 4= 
<gadget id="calculator">100 * 4</gadget>
<output>400</output>
400 m.   Answer: Option 400
<result>D</result>
A train covers a distance of 18 km in 3 min. If it takes 4 sec to pass a telegraph post, then the length of the train is?