Answer:
The distance is 280 miles
Explanation:
Given
When going to the mountain:
Let the speed be x.


When going home:


Required
Determine the distance of the mountains
Distance is calculated as:

When going to the mountains, the distance is:

When going home, the distance is:

It should be noted that, the distance is the same.
So, we have:

Open bracket


Collect Like Terms


Divide both sides by 3


Substitute 35 for x in



The distance is 280 miles