We have a graph that relates elevation (in the x-axis) with temperature (in the y-axis).
As we have points for elevations between 500 m and 2250 m, we have to extrapolate for an elevation of 3000 m.
We will extrapolate grpahically and get:
The extrapolation give us, for an elevation of 3000 m, a temperature of approximately 3 °C.
Answer: For an elevation of 3000 m, we estimate a temperature of 3 °C.