A Superfast train overtakes two persons walking along a railway track. The first one walks at 9 km/hr. The other one walks at 10.8 km/hr. The train needs 16.8and 17seconds respectively to overtake them. What is the speed of the train if both the persons are walking in the same direction as the train? A) 250 kmph B) 487kmph C) 162kmph D) 312kmph