Two trains of length 100 meters and 200 meters are 660 meters apart. They are moving towards each other on parallel tracks, at speeds of 90 km/h and 108 km/h. After how many seconds will the trains meet?  Choose the correct choice from the following
A) 12  B) 14  C) 16  D) 18  E) 20
The speeds are 90000/3600= 
<gadget id="calculator">90000/3600</gadget>
<output>25</output>
25 m/s and 108000/3600= 
<gadget id="calculator">108000/3600</gadget>
<output>30</output>
30 m/s   The relative speed is 55 m/s.   time= 660 / 55= 
<gadget id="calculator">660 / 55</gadget>
<output>12</output>
12 seconds   The answer is 12.
<result>A</result>
Two trains of length 100 meters and 200 meters are 660 meters apart. They are moving towards each other on parallel tracks, at speeds of 90 km/h and 108 km/h. After how many seconds will the trains meet?