A train passes a platform in 34 seconds. The same train passes a man standing on the platform in 20 seconds. If the speed of the train is 54 km/hr, The length of the platform is  Select the correct option:
A) 280 meter B) 240 meter C) 210 meter D) 200 meter E) None of these
Explanation:   Speed of the train = 54 km/hr = (54×10)/34 m/s = 15 m/s   Length of the train = speed × time taken to cross the man = 15×20 = 300 m   Let the length of the platform = L   Time taken to cross the platform = (300+L)/15   =&gt; (300+L)/15 = 34   =&gt; 300+L = 15×34 = 510   =&gt; L = 510-300= 
<gadget id="calculator">510-300</gadget>
<output>210</output>
210 meter   Answer: Option 210 meter
<result>C</result>
A train passes a platform in 34 seconds. The same train passes a man standing on the platform in 20 seconds. If the speed of the train is 54 km/hr, The length of the platform is