A train passes a station platform in 36 sec and a man standing on the platform in 21 sec. If the speed of the train is 54 km/hr. What is the length of the platform?	Pick one
A) 288
B) 225
C) 881
D) 1277
E) 121
Speed = 54 * 5/18= 
<gadget id="calculator">54 * 5/18</gadget>
<output>15</output>
15 m/sec.   Length of the train= 15 * 21= 
<gadget id="calculator">15 * 21</gadget>
<output>315</output>
315 m.   Let the length of the platform be x m . Then,   (x + 315)/36= 15 =&gt; x = 225 m.   Answer: 225
<result>B</result>
A train passes a station platform in 36 sec and a man standing on the platform in 21 sec. If the speed of the train is 54 km/hr. What is the length of the platform?