Now upper surface of plate 3 (potential is V) and lower surface of plate 2 (potential V2) form a capacitor C1. The upper surface of plate 2 and lower surface of plate 1 (potential V1) form a capacitor C2 which is in series connection with C1. Similarly, the lower surface of plate 4 (potential V1) and upper surface of plate 5 (potential 0) form a capacitor C3 which is in series connection with C2. The lower surface of plate 3 (potential V) and upper surface of plate 4 (potential V1) form a capacitor C4 which is in parallel connection with the series combination C1 and C2.
Here all capacitors have same capacitance C =
.
So, the equivalent capacitance of C1 and C2 is
 and equivalent capacitance of C1
and C2 and C3 is
 + C =
. The net capacitance of the combination is
 =
.