A man in a train notices that he can count 51 telephone posts in one minute. If they are known to be 100 metres apart, then at what speed is the train travelling?  Select the correct option.
A) 250km/hr
B) 150km/hr
C) 225km/hr
D) 300km/hr
E) 315km/hr
Number of gaps between 51 telephone posts = 50   distance travelled in 1 minute = 100*50= 
<gadget id="calculator">100*50</gadget>
<output>5_000</output>
5000m= 5km   speed = 300km/hr   Answer is 300km/hr
<result>D</result>
A man in a train notices that he can count 51 telephone posts in one minute. If they are known to be 100 metres apart, then at what speed is the train travelling?