Answer:

where the elevation, h, is in feet and time, t, is in minutes.
Step-by-step explanation:
At the time,  min, the elevation,
 min, the elevation,  feet and
 feet and
at the time  min, the elevation,
 min, the elevation,  feet.
 feet.
As they are hiking a steady incline, so the change in the elevation with respect to time will be constant.
So, there will be a linear relationship between the elevation and the time.
Let  be the elevation at any time instant
 be the elevation at any time instant  , so the linear relation among these quantities is
, so the linear relation among these quantities is

where  is the rate of change of elevation with respect to time and
 is the rate of change of elevation with respect to time and  is constant.
 is constant.
The change in the elevation,  feet.
 feet.
and the change in time,  min.
 min.
So, change in the elevation in unit time,
 feet/min.
 feet/min.
Now, from equation (i)

As the elevation,  at time
 at time  , so
, so


Hence, the required equation is

where the elevation,  , is in feet and time,
, is in feet and time,  , is in minutes.
, is in minutes.