Question

John cycles the first 350 km of 470 km average speed and the remaining distance at an average speed that is 15 km per hour less than that for the first part of the journey if the time taken for him to travel each part of his journey is the same find the average speed for the second part of the journey

Answer 1

Let the average speed for the first part of the journey be x km/h.

Since the time taken for both parts of the journey is the same, the total time taken for the first part of the journey is equal to the total time taken for the second part of the journey.

Time taken for the first part of the journey = Distance / Speed
Time taken for the second part of the journey = Distance / (Speed - 15)

350 / x = 120 / (x - 15)

Cross multiply to get:

350(x - 15) = 120x
350x - 5250 = 120x
230x = 5250
x = 22.83 km/h

Therefore, the average speed for the second part of the journey is 22.83 - 15 = 7.83 km/h.