A train passes a station platform in 30 sec and a man standing on the platform in 12 sec. If the speed of the train is 54 km/hr. What is the length of the platform?  Choices.
A) 227 B) 240 C) 200 D) 178 E) 270
Speed = 54 * 5/18= 
<gadget id="calculator">54 * 5/18</gadget>
<output>15</output>
15 m/sec.   Length of the train= 15 * 12= 
<gadget id="calculator">15 * 12</gadget>
<output>180</output>
180 m.   Let the length of the platform be x m . Then,   (x + 180)/30= 15 =&gt; x = 270 m.   Answer:270
<result>E</result>
A train passes a station platform in 30 sec and a man standing on the platform in 12 sec. If the speed of the train is 54 km/hr. What is the length of the platform?