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?  Select.
A) 100m B) 75m C) 120m D) 50m E) 70m
since both trains move in same direction so:   average speed=50-32= 
<gadget id="calculator">50-32</gadget>
<output>18</output>
18kmph=5mps   speeed=length of train /time   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?