Question

Mr. John took 5 hours to cover 3/5of a journey. He covered the remaining 200 km in 3 hours. What ishis average speed for the whole journey?

Answer 1

Given,

The time taken by Mr. john to cover 3/5 of the journey is 5 hours.

The distance covered by Mr, john in 3 hour is 200 km.

Consider,

The complete distance covered by the Mr john in the journey is x km.

According to the question,

`\begin{gathered} x-(3)/(5)x=200km \\ 5x-3x=5*200km \\ 2x=1000km \\ x=(1000km)/(2) \\ x=500km \end{gathered}`

The total distance covered by the Mr. john in the journey is 500 km.

The distance covered by him in 3 hours is 200 km.

The distance covered by him in 5 hour is,

`(3)/(5)x=(3)/(5)*500=300km`

The average speed of the whole journey is,

`\begin{gathered} Average\text{ speed=}\frac{total\text{ distance}}{total\text{ time}} \\ =(500)/(5+3) \\ =(500)/(8) \\ =62.5km\text{ per hour} \end{gathered}`

Hence, the average speed for the whole journey is 62.5 km per hour.