A boy sitting in a train which is travelling at 30 kmph observes that a goods train travelling in a opposite direction, takes 18 seconds to pass him. If the goods train is 350 m long, find its speed.  Choose the correct choice from the following:  A) 25  B) 30  C) 35  D) 40  E) 45
Relative speed = (350/18)m/s = (350/18)*(18/5)= 
<gadget id="calculator">(350/18)*(18/5)</gadget>
<output>70</output>
70 kmph   speed of goods train= 70-30= 
<gadget id="calculator">70-30</gadget>
<output>40</output>
40 kmph   Answer is 40
<result>D</result>
A boy sitting in a train which is travelling at 30 kmph observes that a goods train travelling in a opposite direction, takes 18 seconds to pass him. If the goods train is 350 m long, find its speed.