Two trains from opposite directions are to cross each other. The length of two trains are 100 meter and 200 meter respectively. The speed of first train is 100 km/hour and second train 200 km/hour. In how much time will they cross each other?
Choose the correct choice from the following options:	A) 2 second	B) 3.6 second	C) 5 second	D) 5.5 second	E) 6 second
The crossing moment starts when the head of first compartment of two trains meet or touch. The process of crossing each other continues till 100 + 200= 
<gadget id="calculator">100 + 200</gadget>
<output>300</output>
300 meter is covered. The speed will be 100km/hour + 200 km/hour= 300 km/hour. 300x1000 meter covered in 3600 seconds. So, 300 meter covered in 3.6 seconds.   Answer: 3.6 second.
<result>B</result>
Two trains from opposite directions are to cross each other. The length of two trains are 100 meter and 200 meter respectively. The speed of first train is 100 km/hour and second train 200 km/hour. In how much time will they cross each other?