A train covers a distance of 12 km in 10 min. If it takes 7 sec to pass a telegraph post, then the length of the train is?  Choose the most appropriate option:
A) 177 m B) 189 m C) 140 m D) 178 m E) 188 m
Speed = (12/10 * 60) km/hr = (72 * 5/18) m/sec   = 20 m/sec.   Length of the train = 20 * 7= 
<gadget id="calculator">20 * 7</gadget>
<output>140</output>
140 m.   Answer: 140 m
<result>C</result>
A train covers a distance of 12 km in 10 min. If it takes 7 sec to pass a telegraph post, then the length of the train is?