A man walks at 4 km/hr on plain, then at 3 km/hr uphill and then returns…
2025
A man walks at 4 km/hr on plain, then at 3 km/hr uphill and then returns through the same road at 6 km/hr downhill and at 4 km/hr on the plain. It takes altogether 6 hours. So what distance he covered in one way?
- A.
24 km
- B.
14 km
- C.
22 km
- D.
6 km
Attempted by 9 students.
Show answer & explanation
Correct answer: A
Key idea: write the total time for both directions and solve for the one-way distance.
Let x be the plain distance (one way) and y be the uphill distance (one way). The one-way distance is x + y.
Outward time: plain at 4 km/h gives x/4 hours; uphill at 3 km/h gives y/3 hours.
Return time: downhill at 6 km/h gives y/6 hours; plain at 4 km/h gives x/4 hours.
Total time = x/4 + y/3 + y/6 + x/4 = x/2 + y/2 = (x + y)/2.
Given total time is 6 hours, set (x + y)/2 = 6, so x + y = 12.
Conclusion: The one-way distance is 12 km.