Calculate the ratio of the drag force on a passenger jet flying with a speed of 750 km/h at an altitude of 10 km to the drag force on a prop-driven transport flying at one-fifth the speed and half the altitude of the jet. At 10 km the density of air is 0.38 kg/m3 and at 5.0 km it is 0.67 kg/m3. Assume that the airplanes have the same effective cross-sectional area and the same drag coefficient C.

Question

Calculate the ratio of the drag force on a passenger jet flying with a speed of 750 km/h at an altitude of 10 km to the drag force on a prop-driven transport flying at one-fifth the speed and half the altitude of the jet. At 10 km the density of air is 0.38 kg/m3 and at 5.0 km it is 0.67 kg/m3. Assume that the airplanes have the same effective cross-sectional area and the same drag coefficient C. 
(drag on jet / drag on transport.

Please help :)

You must have been given some equations for drag force, these equations vary, but typically they depend on Area, a coefficeint, and velocity^2.

Post your equations and work, and I will critique.

Sorry, the equation given is:

D=1/2(Dp)(Area)(Velocity^2)

I do not understand what area I am trying to calculate and what the constant equals. How do I find Dp and Area???