Two trains move in the same direction at speeds 50 kmph and 32 kmph respectively. A man in the slower train observes that 15 seconds elapse before the faster train completely passes by him. What is the length of faster train? Choose the most appropriate option:
A) 100m  B) 75m  C) 120m  D) 50m  E) 40m
As both trains move in same direction, the relative velocity is (50-32)Km/hr   =&gt; Velocity = 18Km/hr = 18*(5/18) m/s = 5m/s   As 15seconds is the total time taken by the train,   =&gt; Length of train = 5*15= 
<gadget id="calculator">5*15</gadget>
<output>75</output>
75m   ANSWER:75m
<result>B</result>
Two trains move in the same direction at speeds 50 kmph and 32 kmph respectively. A man in the slower train observes that 15 seconds elapse before the faster train completely passes by him. What is the length of faster train?