A train passes a station platform in 60 sec and a man standing on the platform in 20 sec. If the speed of the train is 54 km/hr. What is the length of the platform?
Choose the correct choice:
A) 615 m	B) 420 m	C) 168 m	D) 197 m	E) 691 m
Speed = 54 * 5/18= 
<gadget id="calculator">54 * 5/18</gadget>
<output>15</output>
15 m/sec.   Length of the train= 15 * 20= 
<gadget id="calculator">15 * 20</gadget>
<output>300</output>
300 m.   Let the length of the platform be x m . Then,   (x + 300)/36= 15 =&gt; x   = 420 m   Answer: 420 m
<result>B</result>
A train passes a station platform in 60 sec and a man standing on the platform in 20 sec. If the speed of the train is 54 km/hr. What is the length of the platform?