Electric times!

$A:$ The equivalent capacitance between the terminals $A$ and $B$ is $\frac{x}{10}$ $\frac{A*\epsilon}{d}$ .

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$B:$ Figure shows a system of three concentric metal shells $A,B$ and $C$ with radii $a,2a$ and $3a$ respectively.Shell $B$ is earthed and shell $C$ is given a charge $Q$ .Now if shell $C$ is connected to shell $A$ ,then the final charge on the shell $B$ is $\frac{-Q*y}{11}$

$C:$ Four infinite ladder network containing identical resistances of $R$ ohm each,are combined as shown in the figure.The equivalent resistances between $A$ and $B$ is $R_{AB}$ and between $A$ and $C$ is $R_{AC}$ .Let $\frac{R_{AB}}{R_{AC}}=z$ .

Find $x+y+z$