Correct Answer - Option 4 : 6.5 km
Given Data:
Uphill rate = 2.5 km/hr
Downhill rate = 3.25 km/hr
Formula Used:
Distance = speed × Time
Calculation:
Let the distance he walked up the hill be x km.
So, the distance he walked down the hill is x km.
Now, According to the question
x/2.5 + x/3.25 = 4 + 36/60
⇒ 10x/25 + 100x/325 = 23/5
⇒ (130x + 100x)/325 = 23/5
⇒ 230x = (23 × 325)/5
⇒ 230x = 23 × 65
x = 6.5
∴ the distance he walked up the hill is 6.5 km.