7. A man can walk uphill at the rate of 2.5 km/hr. and downhill at the rate of 3.25 km/hr. If the total time required to walk a certain distance up the hill and return to the starting position is 4 hours. 36 min What is the distance he walked up the hill?

Explanation

Let `x` km is the distance travelled by the man walking up the hill.

Then,

`x/(2.5)+x/3.5 = 4 36/60`...[As 4 hours 36 min = 4 36/60 hours]

`=>x/(2.5)+x/3.5 = 276/60`

`=>24x+18.40x = 276`

`=>42.4x = 276`

`=> x = 6.50km`

So, distance covered by him going uphill is `6.5` km and total distance going up and down is `13` km.