Coaxial Cylindrical Conductors?

Two coaxial cylindrical conductors are shown in cross-section above. The inner cylinder has radius a = 2 cm, length 10 m and caries a total charge of Qinner = + 8 nC (1 nC = 10-9 C). The outer cylinder has an inner radius b = 6 cm, outer radius c = 7 cm, length 10 m and cariies a total charge of Qouter = - 16 nC (1 nC = 10-9 C). What is Ex, the x-component of the electric field at point P which is located at the midpoint of the length of the cylinders at a distance r = 4 cm from the origin and makes an angle of 30o with the x-axis?