Q.  A train covers the journey from A to B at 84 km per hour and returns back to A with a uniform speed of 56km per hour. Distance between two stations A and B is 778 km. Find the average speed of the train during the whole journey? 

1. 64.2 km/hr
2. 65.2 km/hr
3. 67.2 km/hr
4. 63.2 km/hr