As most of you know, commercial transport planes cruise at an altitude of approximately...

As most of you know, commercial transport planes cruise at an altitude of approximately 10,000 m (~33,000 ft). The power required to maintain level flight depends on air drag, or resistance, at that altitude, which may be estimated by the following relationship:

where ρ_air is density of air at the given altitude,C_D represents the drag coefficient of the plane, A is the planform area, and U represents the cruising speed of the plane. Assume that a plane is moving at constant speed and, C_D remaining constant, determine the ratio of power that would be required if the plane is cruising at 8000 m and when the plane may be cruising at 11,000 m.