Electrostatic Potential and Capacitance Part 2

Space between the plates of a parallel plate capacitor of plate area 4cm2 and separation of (d) 1.77 mm , is filled with uniform dielectric materials with dielectric constants ( 3 and 5 )as shown in figure. Another capacitor of capacitance 7.5 pF is connected in parallel with it. The effective capacitance of this combination is ____ pF.
(Given E0=8.85×10−12F∕m )