Question

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?

Answer 1

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 :

`t_1 = (1)/(3)\ hours`

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

`t_2 = (2)/(4)\ hours\\\\ t_2 = (1)/(2)\ hours`

Time taken to walk one mile downhill is :

`t_3 = (1)/(5)\ hours`

Total time taken :

`T = t_1 + t_2 + t_3 \\\\T = (1)/(3) + (1)/(2)+(1)/(5)\\\\T = (10 + 15 + 6)/(30) \\\\T = (31)/(30)\ hours = (31)/(30)* 60 \ minutes\\\\T = 62\ minutes`

Therefore, time taken un 62 minutes.