Question

Distance between two stations x and y is 778 km. A train covers the journey from x to
y at a speed of 84 kmph and returns to x with a speed of 56 kmph. Find the average
speed of the train (in kmph ) for the whole journey.

Answer 1

Find the time taken to travel from X to Y:

Time = Distance ÷ Speed

Time = 778 ÷ 84 = 389/42 hours

Find the time taken to travel from Y to X:

Time = Distance ÷ Speed

Time = 778 ÷ 56 = 389/28 hours

Find the total time taken:

Total time taken = 389/42 + 389/28 = 1945/84 hours

Find the average speed:

Speed = Total Distance ÷ Total time = ( 778 x 2 ) ÷ 1945/84 = 67.2 km/h

Answer: The average speed is 67.2 km/h