What is the Relationship Between Weight and Wing Loading in Aerodynamics?

[danny2010]

Homework Statement

a) The weight of the aircraft = 4000 N
b) Wing loading of the aircraft = 65N per sq m
c) Find the minimum drag, maximum lift to drag ratio and the minimum drag speed at sea level

Homework Equations

CD = 0.019 + 0.04 CL2
Where CD is coefficient of Drag
CL is coefficient of Lift
CL2 is square of coeff of lift

The Attempt at a Solution

 

[danny2010]

This is one of the common question in aerodynamics. Kindly help me solving this, if possible with theory suppourting the solution. If u are aware of any site possessing a solution for this kind of problem, do let me know.