A man sitting in a train which is travelling at 20 kmph observes that a goods train, travelling in opposite direction, takes 9 seconds to pass him. If the goods train is 280 m long, find its speed?
Choose the most appropriate option:  A) 52 kmph.  B) 62 kmph.  C) 72 kmph.  D) 92 kmph.  E) None
Solution   Relative Speed	= (280 / 9)m/sec   = (280/9 x 18/5)   = 112 kmph.   Speed of the train	= (112 - 20)= 
<gadget id="calculator">(112 - 20)</gadget>
<output>92</output>
92 kmph.   Answer 92 kmph.
<result>D</result>
A man sitting in a train which is travelling at 20 kmph observes that a goods train, travelling in opposite direction, takes 9 seconds to pass him. If the goods train is 280 m long, find its speed?