What is the temperature around an aeroplane flying at an altitude of 4000metres if the temperature on the earth's surface is 40ºc ?

What is the temperature around an aeroplane flying at an altitude of 4000metres if the temperature on the earth's surface is 40ºc $\mathrm{<br>}$?

Answer Details

Lapse rate is simply described as 0.65°C per 100m of ascent or 6.5ºC per 1000m of ascent.
Therefore 4000m of ascent= 6.5ºC x 4000m/1000m=26.0ºC
Then, the temperature around the aeroplane is = 40ºC - 26ºC = 14°C