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

Options

A. `67.0` km/hr
B. `67.2` km/hr
C. `69.0` km/hr
D. `69.2` km/hr

Answer

B