A man sitting in a train which is travelling at 100 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 correct choice.
A) 52 kmph.
B) 62 kmph.
C) 12 kmph.
D) 80 kmph.
E) None
Solution   Relative Speed	= (280 / 9)m/sec   = (280/9 x 18/5)   = 112 kmph.   Speed of the train	= (112 - 100)= 
<gadget id="calculator">(112 - 100)</gadget>
<output>12</output>
12 kmph.   Answer 12 kmph.
<result>C</result>
A man sitting in a train which is travelling at 100 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?