Two trains are moving in opposite directions @100kmph and 120kmph. Their length are 500m and 700m. The time taken by the slower train to cross faster train in second is?  Choose the correct answer:
A) 15sec  B) 18.3sec  C) 19.6sec  D) 20.4sec  E) 22.5sec
Relative speed = 100+120= 
<gadget id="calculator">100+120</gadget>
<output>220</output>
220*5/18= 550/9 m/s   Distance covered = 500+700= 
<gadget id="calculator">500+700</gadget>
<output>1_200</output>
1200m   Required time= 1200*9/550 = 19.6sec   Answer is 19.6sec
<result>C</result>
Two trains are moving in opposite directions @100kmph and 120kmph. Their length are 500m and 700m. The time taken by the slower train to cross faster train in second is?