Question

a man traveled from the village to the post-office at the rate of 25 kmph and walked back at the rate of 4 kmph. if the whole journey took 5 hours 48 minutes, find the distance of the post-office from the village ?

Answer 1

If x is the speed one way and y the other way

then the average speed is

v = 2xy/(x+y)  

here x=25, y=4

v=100/29

or d/t=100/29

now t= 5 hrs 48 min = 5 4/5 hrs = 29/5 hrs

hence d = 100/29*29/5 = 20 km.

Hope it helps u.

Answer 2

Let the distance be x

Express the duration going to the post office in term of x:

Time = Distance ÷ Speed

Time = x/25 hour

Express the duration going back to the village in term of x:

Time = Distance ÷ Speed

Time = x/4 hour

Solve x:

Given that the time taken is 5 hours 48 mins

5 hours 48 min = 5 4/5 hour = 29/5 hours

x/25 + x/4 = 29/5

29/100 x= 29/5

x = 29/5 ÷ 29/100 = 20km

Answer: The distance is 20 km