Xinran walks 3 mi/h uphill, 4 mi/h on flat land and 5 mi/h downhill. If he walks one mile uphill, then one mile on flat land and then returns by the same route to his starting point, how many minutes does he walk?

Given :

Xinran walks 3 mi/h uphill, 4 mi/h on flat land and 5 mi/h downhill.

To Find :

If he walks one mile uphill, then one mile on flat land and then returns by the same route to his starting point, how many minutes does he walk.

Solution :

Time taken to walk one mile uphill is :

Time taken to walk two mile on flat land( one on going and one or returning ) is :

Time taken to walk one mile downhill is :

Total time taken :

Therefore, time taken un 62 minutes.